0001628280-21-002861 | 10-K | XBRL Viewer

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Cover Page - USD ($)	12 Months Ended
Cover Page - USD ($)	Dec. 31, 2020	Feb. 17, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	000-50679
Entity Registrant Name	CORCEPT THERAPEUTICS INC
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	77-0487658
Entity Address, Address Line One	149 Commonwealth Drive
Entity Address, City or Town	Menlo Park
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94025
City Area Code	650
Local Phone Number	327-3270
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	CORT
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 1,632,998,185
Entity Common Stock, Shares Outstanding		117,312,341
Documents Incorporated by Reference	Portions of the Registrant’s definitive proxy statement for its 2021 Annual Meeting of Stockholders are incorporated by reference in Items 10, 11, 12, 13 and 14 of Part III.
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0001088856

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 76,190	$ 31,269
Short-term marketable securities	364,506	244,693
Trade receivables, net of allowances	26,198	19,928
Inventory	4,910	5,424
Prepaid expenses and other current assets	6,697	6,044
Total current assets	478,501	307,358
Strategic inventory	16,247	11,981
Operating lease right-of-use asset	2,509	3,446
Property and equipment, net of accumulated depreciation	1,675	1,050
Long-term marketable securities	36,196	39,352
Other assets	5,000	3,448
Deferred tax assets, net	31,603	45,677
Total assets	571,731	412,312
Current liabilities:
Accounts payable	10,554	7,537
Accrued clinical expenses	13,704	6,477
Accrued and other liabilities	21,186	23,269
Short-term operating lease liability	2,050	1,558
Total current liabilities	47,494	38,841
Long-term operating lease liability	501	1,903
Long-term accrued income taxes	398	386
Total liabilities	48,393	41,130
Commitments and contingencies (Note 10)
Stockholders’ equity:
Preferred stock, par value $0.001 per share, 10,000 shares authorized and no shares outstanding at December 31, 2020 and December 31, 2019	0	0
Common stock, par value $0.001 per share, 280,000 shares authorized and 122,586 issued and 116,735 outstanding at December 31, 2020 and 119,767 shares issued and 114,549 outstanding at December 31, 2019	122	120
Treasury stock; at cost; 5,851 shares of common stock at December 31, 2020 and 5,218 shares of common stock at December 31, 2019	(75,795)	(62,704)
Additional paid-in capital	516,140	457,060
Accumulated other comprehensive gain	415	261
Retained earnings (accumulated deficit)	82,456	(23,555)
Total stockholders’ equity	523,338	371,182
Total liabilities and stockholders’ equity	$ 571,731	$ 412,312

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	280,000,000	280,000,000
Common stock, shares, issued (in shares)	122,586,000	119,767,000
Common stock, shares, outstanding (in shares)	116,735,000	114,549,000
Treasury stock (in shares)	5,851,000	5,218,000

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Product revenue, net	$ 353,874	$ 306,486	$ 251,247
Operating expenses:
Cost of sales	5,582	5,504	5,215
Research and development	114,764	89,017	75,247
Selling, general and administrative	105,326	100,359	81,289
Total operating expenses	225,672	194,880	161,751
Income from operations	128,202	111,606	89,496
Interest and other income	3,400	5,070	2,657
Income before income taxes	131,602	116,676	92,153
Income tax expense	25,591	22,495	16,743
Net income	106,011	94,181	75,410
Other comprehensive income:
Net unrealized (loss) gain on available-for-sale investments, net of tax impact of $15, $(104) and $22	(50)	327	5
Foreign currency translation gain, net of tax	204	4	0
Total comprehensive income	$ 106,165	$ 94,512	$ 75,415
Basic net income per share (in dollars per share)	$ 0.92	$ 0.82	$ 0.65
Diluted net income per share (in dollars per share)	$ 0.85	$ 0.77	$ 0.60
Weighted average shares outstanding used in computing net income per share
Basic (in shares)	115,412	114,349	115,343
Diluted (in shares)	124,194	122,566	126,688

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net unrealized gain (loss) on available-for-sale investments, tax	$ 15	$ (104)	$ 22

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 106,011	$ 94,181	$ 75,410
Adjustments to reconcile net income to net cash provided by operations:
Stock-based compensation	33,539	29,313	23,747
Amortization (accretion) of interest income	1,303	(1,738)	(1,721)
Depreciation and amortization of property and equipment	525	703	236
Deferred income taxes	14,089	16,877	14,067
Non-cash amortization of right-of-use asset	1,712	1,468	0
Others	148	0	0
Changes in operating assets and liabilities:
Trade receivables	(6,270)	(2,340)	(2,288)
Other receivable	0	0	12,896
Inventory	(3,514)	(1,044)	(7,779)
Prepaid expenses and other current assets	(653)	1,696	(5,071)
Other assets	(1,552)	(3,398)	0
Accounts payable	3,161	(735)	(389)
Accrued clinical expenses	7,227	2,956	1,274
Accrued and other liabilities	(2,083)	(517)	5,044
Long-term accrued income taxes	12	147	239
Operating lease liability	(1,685)	(1,452)	0
Net cash provided by operating activities	151,970	136,117	115,665
Cash flows from investing activities:
Purchases of property and equipment	(1,238)	(1,088)	(298)
Proceeds from maturities of marketable securities	302,089	182,295	142,655
Purchases of marketable securities	(420,114)	(299,035)	(233,124)
Net cash used in investing activities	(119,263)	(117,828)	(90,767)
Cash flows from financing activities:
Proceeds from exercise of stock options, net of issuance costs	23,226	8,419	9,322
Repurchase of common stock	(9,945)	(30,975)	(23,657)
Cash paid to satisfy statutory withholding requirement for the net settlement of cashless option exercise	(1,067)	(6,089)	0
Net cash provided by (used in) financing activities	12,214	(28,645)	(14,335)
Net increase (decrease) in cash and cash equivalents	44,921	(10,356)	10,563
Cash and cash equivalents, at beginning of period	31,269	41,625	31,062
Cash and cash equivalents, at end of period	76,190	31,269	41,625
Supplemental disclosure:
Income taxes paid	10,856	6,744	1,351
Cost of shares repurchased for net settlement of cashless option exercise	2,079	1,983	0
Recognition of right-of-use asset and lease liability	$ 775	$ 4,913	$ 0

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Employees and Directors	Non-employee	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Employees and Directors	Additional Paid-in Capital Non-employee	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit)
Beginning balance (in shares) at Dec. 31, 2017				114,717
Beginning balance at Dec. 31, 2017	$ 190,968			$ 115	$ 384,074			$ 0	$ (75)	$ (193,146)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of options (in shares)	2,100			2,121
Issuance of common stock upon exercise of options	$ 9,322			$ 2	9,320
Stock-based compensation related to employee and director options		$ 23,834				$ 23,834
Other comprehensive loss, net of tax	5								5
Purchases of treasury stock (in shares)				(1,807)
Purchase of treasury stock	(23,657)							(23,657)
Net income	75,410									75,410
Ending balance at Dec. 31, 2018	$ 275,882			$ 117	417,228			(23,657)	(70)	(117,736)
Ending balance (in shares) at Dec. 31, 2018				115,031
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of options (in shares)	2,900			2,929
Issuance of common stock upon exercise of options	$ 10,402			$ 3	10,399
Shares tendered to satisfy cost and statutory withholding requirements for net settlement of cashless option exercises (in shares)				(631)
Shares tendered to satisfy cost and statutory withholding requirements for net settlement of cashless option exercises	(8,072)							(8,072)
Stock-based compensation related to employee and director options		29,201	$ 232			29,201	$ 232
Other comprehensive loss, net of tax	331								331
Purchases of treasury stock (in shares)				(2,780)
Purchase of treasury stock	(30,975)							(30,975)
Net income	94,181									94,181
Ending balance at Dec. 31, 2019	$ 371,182			$ 120	457,060			(62,704)	261	(23,555)
Ending balance (in shares) at Dec. 31, 2019				114,549
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of options (in shares)	2,819			2,819
Issuance of common stock upon exercise of options	$ 25,305			$ 2	25,303
Shares tendered to satisfy cost and statutory withholding requirements for net settlement of cashless option exercises (in shares)				(154)
Shares tendered to satisfy cost and statutory withholding requirements for net settlement of cashless option exercises	(3,146)							(3,146)
Stock-based compensation related to employee and director options		$ 33,777				$ 33,777
Other comprehensive loss, net of tax	154								154
Purchases of treasury stock (in shares)				(479)
Purchase of treasury stock	(9,945)							(9,945)
Net income	106,011									106,011
Ending balance at Dec. 31, 2020	$ 523,338			$ 122	$ 516,140			$ (75,795)	$ 415	$ 82,456
Ending balance (in shares) at Dec. 31, 2020				116,735

Basis of Presentation and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Basis of Presentation and Summary of Significant Accounting Policies

Description of Business and Basis of Presentation

Corcept Therapeutics Incorporated is a commercial-stage pharmaceutical company engaged in the discovery and development of medications that treat severe metabolic, oncologic and psychiatric disorders by modulating the effect of the hormone cortisol. In 2012, the U.S. Food and Drug Administration (“FDA”) approved Korlym (“mifepristone”) 300 mg tablets, as a once-daily oral medication for the treatment of hyperglycemia secondary to hypercortisolism in adult patients with endogenous Cushing’s syndrome who have type 2 diabetes mellitus or glucose intolerance and have failed surgery or are not candidates for surgery. We have discovered and patented four structurally distinct series of selective cortisol modulators, consisting of more than 1,000 compounds. We are developing compounds from these series as potential treatments for a broad range of serious disorders.

We were incorporated in the State of Delaware in May 1998. Our headquarters are located in Menlo Park, California.

Basis of Presentation

The consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”).

Principles of Consolidation

Our consolidated financial statements include the financial position and results of operations of Corcept Therapeutics UK Limited, our wholly owned subsidiary, which we incorporated in the United Kingdom in March 2017.

Use of Estimates

The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ materially from those estimates.

We reevaluate our estimates and assumptions each quarter, including those related to revenue recognition, recognition and measurement of income tax assets and liabilities, inventory, allowances for doubtful accounts and other accrued liabilities, including our bonus accrual, clinical trial accruals and stock-based compensation.

Fair Value Measurements

We value financial instruments using assumptions we believe third-party market participants would use. When choosing which assumptions to make when determining the value of a financial instrument, we look first for quoted prices in active markets for identical instruments (“Level 1 inputs”). If no Level 1 inputs are available, we consider (i) quoted prices in non-active markets for identical instruments; (ii) active markets for similar instruments; (iii) inputs other than quoted prices for the instrument; and (iv) inputs that are not directly observable, but that can be corroborated by observable data (“Level 2 inputs”). In the absence of Level 2 inputs, we rely on unobservable inputs, such as our estimates of the assumptions market participants would use in pricing the instrument (“Level 3 inputs”).

Cash and Cash Equivalents and Marketable Securities

We consider highly liquid investments that will mature in three months or less from the time we purchase them to be cash equivalents. Cash equivalents are valued using Level 1 inputs, which approximate our cost.

We invest the majority of our funds in marketable securities, primarily corporate notes, U.S. Treasury securities, asset-backed securities, commercial paper and repurchase agreements. We classify our marketable securities as available-for-sale securities and report them at fair value as “cash equivalents” or “marketable securities” on our consolidated balance sheet, with related unrealized gains and losses included in stockholders' equity. Realized gains and losses and permanent declines in value are included in “interest and other income (expense)” on our consolidated statement of comprehensive income.

Credit and Concentration Risks

Our cash, cash equivalents and marketable securities are held in one financial institution. We are subject to credit risk from our cash equivalents and marketable securities. We limit our investments to U.S. Treasury obligations and high-grade corporate debt, asset-backed securities and repurchase agreements with less than a 36-month maturity at the time of purchase.

These investments are diversified and do not expose us to concentrations of credit risk. We have never experienced a loss in, or lack of access to, our operating or investment accounts.

We have a single-source manufacturer of mifepristone, the active pharmaceutical ingredient (API), in Korlym - Produits Chimiques Auxiliaires et de Synthèse SA (PCAS). If PCAS is unable or unwilling to manufacture API in the amounts and time frames required, we may not be able to manufacture Korlym in a timely manner. In order to mitigate this risk, we have purchased and hold in inventory a reserve quantity of mifepristone API.

We have a concentration of risk in regard to the distribution of our product. A single specialty pharmacy, Optime Care, Inc. (“Optime”), dispenses Korlym to patients for us. Optime is an independent third party. Its unwillingness or inability to dispense Korlym to patients in a timely manner would harm our business.

We sell the Korlym that Optime dispenses directly to patients, with title to the medicine passing directly from us to the patient upon the patient’s receipt of the drug. Our receivables risk is spread among various third-party payers - pharmacy benefit managers, insurance companies, government programs and private charities. We extend credit to third-party payers based on their creditworthiness. We monitor our exposure and record an allowance against uncollectible trade receivables as necessary. To date, we have not incurred any credit losses.

Inventory and Cost of Sales

Regulatory approval of product candidates is uncertain. Because product manufactured prior to regulatory approval may not be sold unless regulatory approval is obtained, we record the cost of manufacturing our product candidates as research and development expenses at the time such costs are incurred. We capitalize to inventory manufacturing costs related to Korlym.

We value inventory at the lower of cost or net realizable value and determine the cost of inventory we sell using the specific identification method, which approximates a first-in, first-out basis. We assess our inventory levels at each reporting period and write down inventory that is either expected to be at risk of expiration prior to sale, or has a cost basis in excess of its expected net realizable value, or for which there are inventory quantities in excess of expected requirements. We destroy expired inventory and recognize the related costs as cost of sales in that period’s statement of comprehensive income.

Cost of sales also includes the cost of manufacturing Korlym, including materials, third-party manufacturing costs and indirect personnel and other overhead costs, based on the number of Korlym tablets for which we recognize revenue, as well as costs of stability testing, logistics and distribution.

We classify inventory we do not expect to sell or use in clinical studies within 12 months of the balance sheet date as strategic inventory, a non-current asset.

Net Product Revenue

We sell Korlym directly to patients through a single specialty pharmacy. We also sell Korlym to a specialty distributor (“SD”), for which we recognize revenue at the time the SD receives Korlym. SD sales were less than one percent of our net revenue in the years ended December 31, 2020, 2019 and 2018.

To determine our revenue from the sale of Korlym, we (i) identify our contract with each customer; (ii) identify the obligations of Corcept and the customer under the contract; (iii) determine the contracted transaction price; (iv) allocate the transaction price to the contract’s performance obligations, which in our case consists of delivering Korlym to the customer; and (v) recognize revenue once Korlym has been delivered, provided we deem it probable that we will collect the payment due to us.

Confirmation of coverage by private or government insurance or by a third-party charity is a prerequisite for selling Korlym to a patient.

To determine net product revenue, we deduct from sales the cost of our patient co-pay assistance program and our estimates of (a) government chargebacks and rebates, (b) discounts provided to our SD for prompt payment and (c) reserves for expected Korlym returns. We record these estimates at the time we recognize revenue and update them as new information becomes available. Our estimates take into account our understanding of the range of possible outcomes. If results differ from our estimates, we adjust our estimates, causing a change to our net product revenue and earnings. We report any changes in the period they become known, even if they concern transactions occurring in prior periods.

Government Rebates: Korlym is eligible for purchase by, or qualifies for reimbursement from, Medicaid and other government programs that are eligible for rebates on the price they pay for Korlym. To determine the appropriate amount to

reserve against these rebates, we identify Korlym sold to patients covered by government-funded programs, apply the applicable government discount to these sales, then estimate the portion of total rebates we expect will be claimed.

Chargebacks. Although we sell Korlym to the SD at full price, some of the government entities to which the SD sells receive a discount. As it makes such sales, SD recovers the full amount of any related discounts by reducing its payment to us (this reduction is called a “chargeback”). Chargebacks sometimes relate to Korlym purchased by the SD in prior periods. We deduct from our revenue in each period chargebacks claimed by the SD for Korlym it purchased in that period. We also create each period a reserve for chargebacks we estimate the SD will claim in future periods against Korlym it has not yet resold. We determine the amount of this reserve based on our experience with SD chargebacks and our understanding of the SD’s customer base and business practices. We then deduct this reserve from revenue and include in accrued expenses on our consolidated balance sheet a current liability of equal amount.

Patient Assistance Program and Charitable Support: It is our policy that no patient be denied Korlym due to inability to pay. We provide financial assistance to eligible patients whose insurance policies have high deductibles or co-payments and deduct the amount of such assistance from gross revenue. We determine the assistance we provide each patient by applying our program guidelines to that patient’s financial position and their insurance policy’s co-payment and deductible requirements for the purchase of Korlym. We donate cash to charities that help patients with financial need pay for the treatment of Cushing’s syndrome. We do not include payments from these charities in revenue, but as a deduction to selling, general and administrative expenses. We provide Korlym at no cost to uninsured patients who do not qualify for charitable support.

Sales Returns: Federal law prohibits the return of Korlym sold to patients. Sales to our SD are subject to return. We deduct the amount of Korlym we estimate the SD will return from each period’s gross revenue. We base our estimates on quantitative and qualitative information including, but not limited to, historical return rates, the amount of Korlym held by the SD and projected demand. If we cannot reasonably estimate returns with respect to a particular sale, we defer recognition of revenue until we can make a reasonable estimate. To date, returns have not been significant.

The following table summarizes activity in each of the product revenue allowance and reserve categories for the year ended December 31, 2020:


	Chargebacks		Government Rebates		Total
	(in thousands)
Balance at December 31, 2017:	$	927	$	7,961	$	8,888
Provision recorded during the period	2,687		28,628		31,315
Provision related to prior period sales	—		532		532
Credit or payments made during the period	(3,268)		(25,988)		(29,256)
Balance at December 31, 2018:	346		11,133		11,479
Provision related to current period sales	783		24,374		25,157
Provision related to prior period sales	—		(95)		(95)
Credit or payments made during the period	(852)		(27,203)		(28,055)
Balance at December 31, 2019:	277		8,209		8,486
Provision related to current period sales	519		27,698		28,217
Provision related to prior period sales	(3)		(631)		(634)
Credit or payments made during the period	(630)		(25,864)		(26,494)
Balance at December 31, 2020:	$	163	$	9,412	$	9,575

Leases

We determine whether an arrangement contains a lease at inception. A contract is or contains a lease if the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. To determine whether a contract is or contains a lease, we consider all relevant facts and circumstances to assess whether the customer has the right to both (i) obtain substantially all of the economic benefits from use of the identified asset and (ii) direct the use of the identified asset.

We recognize right-of-use assets and lease liabilities at lease commencement. We measure lease liabilities based on the present value of lease payments over the lease term discounted using the rate equal to the rate we would pay on a loan with monthly payments and a term equal to the monthly payments and remaining term of our lease. We estimate our incremental borrowing rate based on non-tender bank quotes and an analysis of public companies with debt and credit carrying terms similar to our lease term. We do not include in the lease term options to extend or terminate the lease unless it is reasonably certain at commencement that we will exercise any such options. We account for the lease components separately from non-lease components for our operating leases.

We measure right-of-use assets based on the corresponding lease liabilities adjusted for (i) prepayments made to the lessor at or before the commencement date, (ii) initial direct costs we incur, and (iii) tenant incentives under the lease. We evaluate the recoverability of our right-of-use assets for possible impairment in accordance with our long-lived assets policy. We do not recognize right-of-use assets or lease liabilities for leases with a term of twelve months or less; rather, we recognize the associated lease payments in the consolidated statements of comprehensive income on a straight-line basis over the lease term.

Operating leases are reflected on our consolidated balance sheets as operating lease right-of-use assets, short-term operating lease liabilities and long-term operating lease liabilities.

We begin recognizing operating lease expense when the lessor makes the underlying asset available to us. We recognize operating lease expense under our operating leases on a straight-line basis. Variable lease payments are expensed as incurred.

The Company did not have any finance leases at either December 31, 2020 or 2019.

Research and Development

Research and development expenses include the direct cost of discovering and screening new compounds, pre-clinical studies, clinical trials, manufacturing development, submissions to regulatory agencies and related overhead costs. We expense nonrefundable payments and the cost of technologies and materials used in research and development as we incur them.

We base our accruals for discovery research, preclinical studies and clinical trials on our estimates of work completed, milestones achieved, patient enrollment and past experience with similar activities. Our estimates include assessments of information from contract research organizations and the status of our own research, development and administrative activities.

Segment Reporting

We determine our operating segments based on the way we organize our business, make decisions and assess performance. We have only one operating segment, which is the discovery, development and commercialization of pharmaceutical products.

Stock-Based Compensation

We account for stock-based compensation under the fair value method, based on the value of the award at the grant date. To date, our stock-based compensation has consisted entirely of option grants, which we value using the Black-Scholes model. We recognize stock-based compensation expense over the applicable vesting period, net of estimated forfeitures. If actual forfeitures differ from our estimates, we adjust stock-based compensation expense accordingly.

Income Taxes

We account for income taxes in accordance with ASC 740, Income Taxes (“ASC 740”), which requires recognition of deferred tax assets and liabilities for the expected tax consequences of our future financial and operating activities. Under ASC 740, we determine deferred tax assets and liabilities based on the temporary difference between the financial statement and tax bases of assets and liabilities using the tax rates in effect for the year in which we expect such differences to reverse. If we determine that it is more likely than not that we will not generate sufficient taxable income to realize the value of some or all of our deferred tax assets (net of our deferred tax liabilities), we establish a valuation allowance offsetting the amount we do not expect to realize. We perform this analysis each reporting period and reduce our measurement of deferred taxes, if the likelihood we will realize them becomes uncertain.

The deferred tax assets we record each period depend primarily on our ability to generate future taxable income in the United States. Each period, we evaluate the need for a valuation allowance against our deferred tax assets and, if necessary, adjust the valuation allowance so that net deferred tax assets are recorded only to the extent we conclude it is more likely than

not that these deferred tax assets will be realized. If our outlook for future taxable income changes significantly, our assessment of the need for, and the amount of, a valuation allowance may also change.

We are also required to evaluate and quantify other sources of taxable income, such as the possible reversal of future deferred tax liabilities, should any arise, and the implementation of tax planning strategies. Evaluating and quantifying these amounts is difficult and involves significant judgment, based on all of the available evidence and assumptions about our future activities.

We account for uncertain tax positions in accordance with ASC 740, which requires us to adjust our consolidated financial statements to reflect only those tax positions that are more-likely-than-not to be sustained upon review by federal or state examiners. We recognize in the consolidated financial statements the largest expected tax benefit that has a greater than 50 percent likelihood of being sustained on examination by the taxing authorities. We report interest and penalties related to unrecognized tax benefits as income tax expenses.

Recently Adopted Accounting Pronouncements

In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments-Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments,” which changes the methodology for measuring credit losses on financial instruments and when such losses are recorded. This standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019. We adopted this standard on January 1, 2020 using the modified retrospective approach with the cumulative effect of the adoption recorded as an adjustment to retained earnings. It had no impact on our consolidated financial statements.

Recently Issued Accounting Pronouncements Not Yet Adopted

In December 2019, the FASB issued ASU No. 2019-12 (ASC Topic 740), “Simplifying the Accounting for Income Taxes.” This standard simplifies accounting for income taxes by removing certain exceptions to the general principles and clarifying existing guidance. This standard will be effective for fiscal years, and interim periods within those years, beginning after December 15, 2020. We will adopt the new standard in the first quarter of 2021. The adoption of this standard is not expected to have a significant impact on our consolidated financial statements.

Significant Agreements	12 Months Ended
Significant Agreements	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Significant Agreements	Significant Agreements Commercial Agreements In August 2017, we entered into a distribution services agreement with an independent third party, Optime, to provide exclusive specialty pharmacy and patient services programs for Korlym beginning August 10, 2017. Under the terms of this agreement, Optime acts as the exclusive specialty pharmacy distributor of Korlym in the United States, subject to certain exceptions. Optime provides services related to pharmacy operations; patient intake, access and reimbursement; patient support; claims management and accounts receivable; and data and reporting. We provide Korlym to Optime, which it dispenses to patients. Optime does not purchase Korlym from us and it does not take title to the product. Title passes directly from us to the patient at the time the patient receives the medicine. The initial term of our agreement with Optime is five years, unless terminated earlier by us upon 90 days’ notice. The agreement contains additional customary termination provisions, representations, warranties and covenants. Subject to certain limitations, we have agreed to indemnify Optime for certain third-party claims related to the product, and we have each agreed to indemnify the other for certain breaches of representations, warranties, covenants and other specified matters. Manufacturing Agreements Related to Korlym We purchase all of our API for Korlym from PCAS. On July 25, 2018, we amended our agreement with PCAS to add a second manufacturing site and extend its term to December 31, 2021, with two one-year automatic renewals, unless either party provides 12 months advance written notice of its intent not to renew. The amendment provides exclusivity between PCAS and Corcept. In the event PCAS cannot meet our requirements, we may purchase API from another supplier. As of December 31, 2020, there were no minimum future purchase obligations under this agreement. We have agreements with two third-party manufacturers to produce and bottle Korlym tablets. Lease Agreement See discussion below in Note 5, Leases, regarding our office lease.

Available-for-Sale Securities and Fair Value Measurements

12 Months Ended

Dec. 31, 2020

Available For Sale Securities And Fair Value Measurements [Abstract]

Available for Sale Securities and Fair Value Measurements

The available-for-sale securities in our Consolidated Balance Sheets are as follows:


	Year Ended December 31,
	2020		2019
	(in thousands)
Cash equivalents	$	50,524	$	18,461
Short-term marketable securities	364,506		244,693
Long-term marketable securities	36,196		39,352
Total marketable securities	$	451,226	$	302,506

The following table presents our available-for-sale securities grouped by asset type:


	Fair Value Hierarchy Level	December 31, 2020								December 31, 2019
		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
		(in thousands)
Corporate bonds	Level 2	$	96,999	$	74	$	(9)	$	97,064	$	109,780	$	136	$	(6)	$	109,910
Commercial paper	Level 2	139,791		—		—		139,791		41,237		—		—		41,237
Asset-backed securities	Level 2	39,243		15		(1)		39,257		57,195		63		(5)		57,253
Repurchase agreements	Level 2	—		—		—		—		18,000		—		—		18,000
U.S. treasury securities	Level 1	124,461		131		(2)		124,590		75,574		71		—		75,645
Money market funds	Level 1	50,524		—		—		50,524		461		—		—		461
Total Marketable securities		$	451,018	$	220	$	(12)	$	451,226	$	302,247	$	270	$	(11)	$	302,506

We estimate the fair value of marketable securities classified as Level 1 using quoted market prices for these or similar investments obtained from a commercial pricing service. We estimate the fair value of marketable securities classified as Level 2 using inputs that may include benchmark yields, reported trades, broker/dealer quotes and issuer spreads.

We periodically review our debt securities to determine if any of our investments is impaired due to credit-related or other issues. If the fair value of our investment in any debt security is less than our amortized cost basis, we determine whether an allowance for credit losses is appropriate by assessing quantitative and subjective factors including, but not limited to, the nature of security, changes in credit ratings, analyst reports concerning the security’s issuer and industry, interest rate fluctuations and general market conditions.

Unrealized losses on our available-for-sale debt securities as of December 31, 2020 were not significant and were primarily due to changes in interest rates, and not increased credit risk. Accordingly, we have not recorded an allowance for credit losses associated with these investments.

We do not intend to sell the investments that are currently in an unrealized loss position, and it is highly unlikely that we will be required to sell the investments before recovery of their amortized cost basis, which may be maturity.

We classified accrued interest on our marketable securities of $1.3 million and $1.0 million as of December 31, 2020 and 2019, respectively, as prepaid and other current assets on our consolidated balance sheet.

As of December 31, 2020, all our marketable securities had original maturities of less than two years. The weighted-average maturity of our holdings was five months. As of December 31, 2020, our long-term marketable securities had remaining maturities ranging from 13 to 17 months. None of our marketable securities changed from one fair value hierarchy to another during the year ended December 31, 2020.

Composition of Certain Balance Sheet Items

12 Months Ended

Dec. 31, 2020

Balance Sheet Related Disclosures [Abstract]

Composition of Certain Balance Sheet Items

Inventory


	Year Ended December 31,
	2020		2019
	(in thousands)
Raw materials	$	1,685	$	1,389
Work in progress	12,916		10,086
Finished goods	6,556		5,930
Total inventory	21,157		17,405
Less strategic inventory classified as non-current	(16,247)		(11,981)
Total inventory classified as current	$	4,910	$	5,424

Because we rely on a single manufacturer for the API for Korlym, we have purchased and hold significant quantities of API. We classify inventory we do not expect to sell within 12 months of the balance sheet date as “Strategic Inventory,” a long-term asset.

Property and Equipment


	Year Ended December 31,
	2020		2019
	(in thousands)
Furniture and equipment	$	810	$	304
Software	1,485		1,541
Leasehold improvements	1,233		533
	3,528		2,378
Less accumulated depreciation	(1,853)		(1,328)
Property and equipment, net of accumulated depreciation	$	1,675	$	1,050

Accrued and other liabilities


	Year Ended December 31,
	2020		2019
	(in thousands)
Accrued compensation	$	10,144	$	12,331
Government rebates	9,412		8,209
Accrued selling and marketing costs	665		491
Legal fees	612		1,087
Professional fees	151		367
Other	202		784
Total accrued and other liabilities	$	21,186	$	23,269

Other assets

As of December 31, 2020 and 2019, other assets includes $4.8 million and $3.3 million of deposits for clinical trials, respectively.

Leases

12 Months Ended

Dec. 31, 2020

Leases [Abstract]

Leases

We lease our office facilities in Menlo Park, California. In January 2019, we recognized a right-of-use asset and a corresponding lease liability of $1.9 million. In October 2019, we amended the lease to extend its term from March 31, 2020 to March 31, 2022 and to add more space beginning April 1, 2020. In June 2020, we amended our lease commencement date for additional space to June 15, 2020. As a result of this amendment, we recognized an additional right-of-use asset and corresponding lease liability of $0.8 million. The right-of-use asset and lease liability recognized equals the present value of the remaining payments due under our amended lease.

As the operating lease for our facilities does not include an expressly stated interest rate, we calculated the present value of remaining lease payments using a discount rate equal to the interest rate we would pay on a loan with monthly payments and a term equal to the monthly payments and remaining term of our lease. We recognize operating lease payments as expenses using the straight-line method over the term of the lease.

Operating lease expense for the years ended December 31, 2020 and 2019 was approximately $1.9 million and $1.5 million, respectively. Rent expense for the year ended December 31, 2018 was $1.3 million.

Our right-of-use assets and related lease liabilities were as follows:


	Year Ended December 31,
	2020			2019
	(in thousands)
Cash paid for operating lease liabilities	$	1,840		$	1,551
Right-of-use assets obtained in connection with operating lease obligations	$	775		$	4,913
Weighted-average remaining lease term (years)	15 months			27 months
Weighted-average discount rate	4.8		%	5.0		%

As of December 31, 2020, future minimum lease payments under non-cancelable operating leases were as follows (in thousands):


2021	$	2,109
2022	530
	2,639
Less imputed interest	(88)
Total operating lease liabilities	$	2,551

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party TransactionsIn February 2020, we purchased from our Chief Executive Officer $0.3 million of our common stock at a price of $13.54 per share, which was the last quoted price per share on the Nasdaq Capital Market on the date of purchase. We purchased the shares in order to provide him with liquidity to satisfy the tax liability arising from his net (cashless) exercise in 2019 of stock options that were about to expire.There were no other related party transactions during the years ended December 31, 2020, 2019, and 2018.

Preferred Stock and Stockholders' Equity

12 Months Ended

Dec. 31, 2020

Equity [Abstract]

Preferred Stock and Stockholders' Equity

Preferred Stock and Stockholders’ Equity

Preferred Stock

Our Board of Directors is authorized, subject to any limitations prescribed by law, without stockholder approval, to issue up to an aggregate of 10,000,000 shares of preferred stock at $0.001 par value in one or more series and to fix the rights, preferences, privileges and restrictions granted to or imposed upon the preferred stock, including voting rights, dividend rights, conversion rights, redemption privileges and liquidation preferences. The rights of the holders of common stock will be subject to the rights of holders of any preferred stock that may be issued in the future. As of December 31, 2020 and 2019, we had no outstanding shares of preferred stock.

Common Stock

Significant stock transactions

On November 3, 2020, we announced that our Board of Directors approved a program to repurchase up to $200 million of our common stock (the “Stock Repurchase Program”). Unless it is terminated or suspended prior to its expiration, the Stock Repurchase Program will remain in effect until September 30, 2021. The timing and amount of any repurchases pursuant to it will be determined based on market conditions, stock price and other factors. The Stock Repurchase Program does not require us to acquire any specific number of shares and it may be modified, suspended or discontinued at any time without notice. Repurchases pursuant to the Stock Repurchase Program may be made through a variety of methods, including open market purchases, privately negotiated transactions, block trades, accelerated share repurchase transactions or any combination of such methods.

During the year ended December 31, 2020, we repurchased 0.5 million shares of common stock under the Stock Repurchase Program in open market transactions at a cost of $9.7 million (average price of $21.08 per share). During the years ended December 31, 2019 and 2018, we repurchased 2.8 million and 1.8 million shares of common stock at a cost of $31.0 million and $23.7 million, respectively, under a Stock Repurchase Program that expired on June 30, 2019. We recorded repurchased shares as treasury stock on our consolidated balance sheet, at cost. We have not decided whether repurchased shares will be retired or sold.

During the years ended December 31, 2020, 2019 and 2018, we issued 2.8 million, 2.9 million and 2.1 million shares, respectively, of our common stock upon the exercise of stock options.

We have never declared or paid any dividends.

Shares of common stock reserved for future issuance as of December 31, 2020 are as follows:


Common stock:			(in thousands)
Exercise of outstanding options			24,946
Shares available for grant under stock option plans			9,041
			33,987

On February 4, 2021, our Board of Directors authorized an additional increase of 4.7 million shares in the number of shares available under the 2012 Equity Incentive Plan (the “2012 Plan”), which was equivalent to 4% of the shares of our common stock outstanding at December 31, 2020.

Stock Option Plans

We have two stock option plans – the 2004 Equity Incentive Plan (the “2004 Plan”) and the 2012 Incentive Award Plan (the “2012 Plan”).

In 2004, our Board of Directors and stockholders approved the 2004 Plan, which became effective upon the completion of our initial public offering (IPO). Under the 2004 Plan, options, stock purchase and stock appreciation rights and restricted stock awards can be issued to our employees, officers, directors and consultants. The 2004 Plan provided that the exercise price for incentive stock options will be no less than 100% of the fair value of the Company’s common stock, as of the date of grant. Options granted under the 2004 Plan vest over periods ranging from one year to five years. The vesting period of the options is generally equivalent to the requisite service period.

In 2012, our Board of Directors and stockholders approved the 2012 Plan. As of the effective date of the 2012 Plan, 5.3 million shares that remained available for issuance of new grants under the 2004 Plan were transferred to the 2012 Plan. After that date, no additional options were or will be issued under the 2004 Plan. Vested options under the 2004 Plan that are not exercised within the remaining contractual life and any options under the 2004 Plan that do not vest because of terminations after the effective date of the 2012 Plan will be added to the pool of shares available for future grants under the 2012 Plan.

Under the 2012 Plan, we can issue options, stock purchase and stock appreciation rights and restricted stock awards to our employees, officers, directors and consultants. The 2012 Plan provides that the exercise price for incentive stock options will be no less than 100 percent of the fair value of our common stock as of the date of grant. Options granted under the 2012 Plan carry a contractual term of ten years and are expected to vest over periods ranging from one year to four years. We assume the vesting period of the options that we grant under the 2012 Plan to be equal to the option grantee’s period of service.

Upon exercise of options, new shares are issued.

Option activity during 2018, 2019 and 2020

The following table summarizes all activity under the 2004 Plan and the 2012 Plan:


		Outstanding Options
	Shares Available For Future Grant	Options Shares Subject to Options Outstanding	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life	Aggregate Intrinsic Value
	(in thousands)	(in thousands)			(in years)	(in thousands)
Balance at December 31, 2019	8,624	23,600	$	8.77
Increase in shares authorized for grant	4,582	—
Shares granted	(5,225)	5,225	$	13.84
Shares exercised	—	(2,819)	$	8.97
Shares canceled and forfeited	1,060	(1,060)	$	13.11
Balance at December 31, 2020	9,041	24,946	$	9.62	6.17	$	412,494

Options exercisable at December 31, 2020		17,047	$	7.83	5.09	$	312,481

Options fully vested and expected to vest at December 31, 2020		24,254	$	9.51	6.10	$	403,738

The total intrinsic value of options exercised during the years ended December 31, 2020, 2019 and 2018 was $28.8 million, $26.6 million and $26.6 million, respectively, based on the difference between the closing price of our common stock on the date of exercise of the options and the exercise price.

The total fair value of options that vested during the years ended December 31, 2020, 2019 and 2018 was $34.0 million, $30.2 million and $22.6 million, respectively.

Stock-Based Compensation related to Employee and Director Options

The following table summarizes the weighted-average assumptions and resultant fair value-based measurements for options granted to employees and directors.


	Year Ended December 31,
	2020	2019	2018
Weighted-average assumptions for stock options granted:
Risk-free interest rate	1.20%	2.34%	2.68%
Expected term	6.0 years	6.0 years	5.9 years
Expected volatility of stock price	59.1%	67.4%	67.9%
Dividend rate	0%	0%	0%
Weighted-average grant date fair value-based measurement	$7.55	$7.09	$10.11

The expected term of options reflected in the table above has been based on a formula that considers the expected service period and expected post-vesting termination behavior depending on whether the option holder is an employee, officer or director.

The expected volatility of our stock used in determining the fair value-based measurement of option grants to employees, officers and directors is based on the volatility of our stock price. The volatility is based on historical data of the price for our common stock for periods of time equal to the expected term of these grants.

We calculate employee stock-based compensation expense using the number of options we expect to vest, based on our estimate of the option grantees’ average length of employment, and reduced by our estimate of option forfeitures. We estimate forfeitures at the time of option grant and revise this estimate in subsequent periods if actual forfeitures differ from our estimates.

As of December 31, 2020, we had $54.8 million of unrecognized compensation expense for employee and director options outstanding as of that date, which had a weighted-average remaining vesting period of 2.39 years.

Summary of Stock-based Compensation

The following table presents a summary of stock-based compensation by financial statement classification.


	Year Ended December 31,
	2020		2019		2018
	(in thousands)
Stock-based compensation capitalized in inventory	$	238	$	120	$	87
Cost of sales	66		144		259
Research and development	11,222		9,541		7,012
Selling, general and administrative	22,251		19,628		16,476
Total stock-based compensation	$	33,777	$	29,433	$	23,834

Net Income Per Share

12 Months Ended

Dec. 31, 2020

Earnings Per Share [Abstract]

Net Income Per Share

We compute basic and diluted net income per share by dividing our net income by the weighted-average number of common shares outstanding during the period. We used the treasury stock method to determine the number of dilutive shares of common stock resulting from the potential exercise of stock options. The statements of consolidated comprehensive income show the computation of net income per share for each period, including the number of weighted-average shares outstanding.

The following table shows the computation of net income per share for each period:


	Year Ended December 31,
	2020		2019		2018
	(in thousands, except per share data)
Numerator:
Net income	$	106,011	$	94,181	$	75,410
Denominator:
Weighted-average shares used to compute basic net income per share	115,412		114,349		115,343
Dilutive effect of employee stock options	8,782		8,217		11,345
Weighted-average shares used to compute diluted net income per share	124,194		122,566		126,688
Net income per share
Basic	$	0.92	$	0.82	$	0.65
Diluted	$	0.85	$	0.77	$	0.60

As of December 31, 2020, 2019, and 2018 we had 24.9 million, 23.6 million, and 22.8 million stock options outstanding, respectively.

Because including them would have reduced dilution, we excluded from the computation of diluted net income per share, on a weighted-average basis 11.2 million, 9.9 million and 5.0 million stock options outstanding during the years ended December 31, 2020, 2019, and 2018, respectively,

Income Taxes

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Income Taxes

The domestic and foreign components of income before income taxes were as follows:


	Year Ended December 31,
	2020		2019		2018
	(in thousands)
Domestic	$	131,634	$	116,676	$	92,153
Foreign	(32)		—		—
Income before income taxes	$	131,602	$	116,676	$	92,153

The income tax expense for the year ended December 31, 2020, 2019, and 2018 consisted of the following:


	Year Ended December 31,
	2020		2019		2018
	(in thousands)
U.S. federal taxes:
Current	$	6,094	$	1,716	$	—
Deferred	14,418		15,944		14,243
Total U.S. federal taxes	20,512		17,660		14,243
State taxes:
Current	5,368		3,900		2,676
Deferred	520		935		(176)
Total state taxes	5,888		4,835		2,500
Foreign taxes:
Current	$	41	$	—	$	—
Deferred	$	(850)	$	—	$	—
Total foreign taxes	(809)		—		—
Total	$	25,591	$	22,495	$	16,743

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our deferred tax assets are as follows:


	Year Ended December 31,
	2020		2019
Deferred tax assets:	(in thousands)
Federal and state net operating losses	$	5,412	$	7,391
Capitalized research and patent costs	5,139		7,317
Research credits	15,107		26,164
Stock-based compensation costs	14,043		12,026
Operating lease liability	630		857
Other	3,473		4,186
Total deferred tax assets	43,804		57,941
Valuation allowance	(11,581)		(11,410)
Deferred tax liabilities
Operating lease right-of-use asset	(620)		(854)
Total deferred tax liabilities	(620)		(854)
Net deferred tax assets	$	31,603	$	45,677

Each quarter, we assess the likelihood that we will generate sufficient taxable income to use our federal and state deferred tax assets. If we believe that recovery of these deferred tax assets is not more likely than not, we will establish a valuation allowance. Significant judgment is required in determining any valuation allowance recorded against deferred tax assets. In assessing the need for a valuation allowance, we consider all available evidence, including recent operating results, projections of future taxable income, our ability to utilize net operating losses and tax credit carryforwards, and the feasibility of tax planning strategies. Other than valuation allowances against our California net deferred tax assets, we have determined that it is more likely than not we will realize the benefit related to all other deferred tax assets. If we increase a valuation allowance, we will include an expense of equal amount in the Condensed Consolidated Statement of Comprehensive Income in the period in which such determination is made.

The valuation allowance increased by $0.2 million and $0.2 million for the years ended December 31, 2020 and 2019, respectively, and decreased by $1.3 million for the year ended December 31, 2018.

At December 31, 2020, we had California net operating loss carryforwards of $75.2 million, which will begin to expire in the year 2032, and net operating loss carryforwards from other states of $2.9 million, which will begin to expire in the year 2024 if not utilized. On June 29, 2020, the California governor signed Assembly Bill 85 (“AB 85”) into law. AB 85 limits the use of business incentive tax credits and suspends the use of California net operating losses for 2020, 2021 and 2022 for companies with taxable income of $1 million or more. AB 85 will not have a material impact on our condensed consolidated financial statements.

At December 31, 2020, we also had federal research and development tax credits of $6.8 million and orphan drug tax credits of $7.8 million, respectively, and California research and development credits of $8.5 million. The federal research credits will expire in the years 2039 through 2040 and the California research credits have no expiration date.

The following table presents a reconciliation from the statutory federal income tax rate to the effective rate.


	Year Ended December 31,
	2020		2019		2018
	(in thousands)
U.S. federal taxes at statutory rate	$	27,636	$	24,502	$	19,354
R&D and other credits	(6,666)		(4,504)		(2,178)
State income taxes	4,651		3,819		1,975
Non-deductible compensation	1,508		657		394
Stock-based compensation	(1,551)		(2,107)		(3,165)
Other	13		128		363
Total	$	25,591	$	22,495	$	16,743

We maintain liabilities for uncertain tax positions. The measurement of these liabilities involves considerable judgment and estimation and are continuously monitored by management based on the best information available, including changes in tax regulations, the outcome of relevant court cases, and other pertinent information.

The aggregate annual changes in the balance of gross unrecognized tax benefits are as follows (in thousands):


	Year Ended December 31,
	2020		2019		2018
Beginning Balance	$	6,029	$	4,756	$	4,139
Increase in tax positions for prior years	158		261		—
Decrease in tax positions for prior years	—		—		(135)
Increase in tax positions for current year	1,284		1,012		752
Decrease in tax positions for current year	—		—		—
Ending Balance	$	7,471	$	6,029	$	4,756

As of December 31, 2020, the amount of unrecognized tax benefits that would favorably impact the effective tax rate were approximately $6.1 million, and approximately $1.4 million of unrecognized tax benefits would be offset by a change in valuation allowance. A valuation allowance is maintained on the remaining tax benefits related to California deferred tax assets and would not impact the effective tax rate. We had no or immaterial amounts of accrued interest and no accrued penalties related to unrecognized tax benefits as of December 31, 2020, 2019 and 2018. We do not expect our unrecognized tax benefits to change materially over the next 12 months.

While we believe we have adequately provided for all tax positions, amounts asserted by tax authorities could be greater or less than the recorded position. Accordingly, our provisions on federal and state tax-related matters to be recorded in the future may change as revised estimates are made or the underlying matters are settled or otherwise resolved.

The Company’s primary tax jurisdiction is the United States. For federal and state tax purposes, the years 1999 through 2020 remain open and subject to tax examination by the appropriate federal or state taxing authorities.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Commitments and contingencies	12 Months Ended
Commitments and contingencies	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	Commitments and contingencies We have entered into a number of agreements to purchase API for the manufacturing of relacorilant, miricorilant and exicorilant. We have also entered into a number of agreements to perform clinical studies on miricorilant and CORT113176. See the discussion in Note 2, Significant Agreements, for further discussion regarding the commitments under these agreements. In March 2020, to ensure we have sufficient API to meet future demand for Korlym tablets, we committed to purchase an additional 400 kilograms of API from Produits Chimiques Auxiliaires et de Synthese SA (“PCAS,” a member of the Seqens Group) for a total price of $5.9 million. As of December 31, 2020, there remained no obligation in connection with this purchase commitment. In the ordinary course of business, we may be subject to legal claims and regulatory actions that could have a material adverse effect on our business or financial position. We assess our potential liability in such situations by analyzing the possible outcomes of various litigation, regulatory and settlement strategies. If we determine a loss is probable and its amount can be reasonably estimated, we accrue an amount equal to the estimated loss. No losses and no provision for a loss contingency have been recorded to date.

Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2020

Quarterly Financial Information Disclosure [Abstract]

Quarterly Financial Data (Unaudited)

The following table is in thousands, except per share amounts:


Quarter Ended	March 31		June 30		September 30		December 31
2020
Product revenue, net	$	93,247	$	88,565	$	86,327	$	85,735
Gross profit on product revenue	91,369		87,331		85,111		84,481
Net income	30,065		28,327		21,625		25,994
Basic net income per share	$	0.26	$	0.25	$	0.19	$	0.22
Diluted net income per share	$	0.25	$	0.23	$	0.17	$	0.20

2019
Product revenue, net	$	64,829	$	72,257	$	81,505	$	87,895
Gross profit on product revenue	63,589		70,880		80,054		86,459
Net income	18,274		20,186		26,340		29,381
Basic net income per share	$	0.16	$	0.18	$	0.23	$	0.26
Diluted net income per share	$	0.15	$	0.17	$	0.22	$	0.24

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”).
Principles of Consolidation	Principles of ConsolidationOur consolidated financial statements include the financial position and results of operations of Corcept Therapeutics UK Limited, our wholly owned subsidiary, which we incorporated in the United Kingdom in March 2017.
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ materially from those estimates. We reevaluate our estimates and assumptions each quarter, including those related to revenue recognition, recognition and measurement of income tax assets and liabilities, inventory, allowances for doubtful accounts and other accrued liabilities, including our bonus accrual, clinical trial accruals and stock-based compensation.
Fair Value Measurements	Fair Value Measurements We value financial instruments using assumptions we believe third-party market participants would use. When choosing which assumptions to make when determining the value of a financial instrument, we look first for quoted prices in active markets for identical instruments (“Level 1 inputs”). If no Level 1 inputs are available, we consider (i) quoted prices in non-active markets for identical instruments; (ii) active markets for similar instruments; (iii) inputs other than quoted prices for the instrument; and (iv) inputs that are not directly observable, but that can be corroborated by observable data (“Level 2 inputs”). In the absence of Level 2 inputs, we rely on unobservable inputs, such as our estimates of the assumptions market participants would use in pricing the instrument (“Level 3 inputs”).
Cash and Cash Equivalents and Marketable Securities	Cash and Cash Equivalents and Marketable Securities We consider highly liquid investments that will mature in three months or less from the time we purchase them to be cash equivalents. Cash equivalents are valued using Level 1 inputs, which approximate our cost. We invest the majority of our funds in marketable securities, primarily corporate notes, U.S. Treasury securities, asset-backed securities, commercial paper and repurchase agreements. We classify our marketable securities as available-for-sale securities and report them at fair value as “cash equivalents” or “marketable securities” on our consolidated balance sheet, with related unrealized gains and losses included in stockholders' equity. Realized gains and losses and permanent declines in value are included in “interest and other income (expense)” on our consolidated statement of comprehensive income.
Credit and Concentration Risks	Credit and Concentration Risks Our cash, cash equivalents and marketable securities are held in one financial institution. We are subject to credit risk from our cash equivalents and marketable securities. We limit our investments to U.S. Treasury obligations and high-grade corporate debt, asset-backed securities and repurchase agreements with less than a 36-month maturity at the time of purchase. These investments are diversified and do not expose us to concentrations of credit risk. We have never experienced a loss in, or lack of access to, our operating or investment accounts. We have a single-source manufacturer of mifepristone, the active pharmaceutical ingredient (API), in Korlym - Produits Chimiques Auxiliaires et de Synthèse SA (PCAS). If PCAS is unable or unwilling to manufacture API in the amounts and time frames required, we may not be able to manufacture Korlym in a timely manner. In order to mitigate this risk, we have purchased and hold in inventory a reserve quantity of mifepristone API. We have a concentration of risk in regard to the distribution of our product. A single specialty pharmacy, Optime Care, Inc. (“Optime”), dispenses Korlym to patients for us. Optime is an independent third party. Its unwillingness or inability to dispense Korlym to patients in a timely manner would harm our business. We sell the Korlym that Optime dispenses directly to patients, with title to the medicine passing directly from us to the patient upon the patient’s receipt of the drug. Our receivables risk is spread among various third-party payers - pharmacy benefit managers, insurance companies, government programs and private charities. We extend credit to third-party payers based on their creditworthiness. We monitor our exposure and record an allowance against uncollectible trade receivables as necessary. To date, we have not incurred any credit losses.
Inventory and Cost of Sales	Inventory and Cost of Sales Regulatory approval of product candidates is uncertain. Because product manufactured prior to regulatory approval may not be sold unless regulatory approval is obtained, we record the cost of manufacturing our product candidates as research and development expenses at the time such costs are incurred. We capitalize to inventory manufacturing costs related to Korlym. We value inventory at the lower of cost or net realizable value and determine the cost of inventory we sell using the specific identification method, which approximates a first-in, first-out basis. We assess our inventory levels at each reporting period and write down inventory that is either expected to be at risk of expiration prior to sale, or has a cost basis in excess of its expected net realizable value, or for which there are inventory quantities in excess of expected requirements. We destroy expired inventory and recognize the related costs as cost of sales in that period’s statement of comprehensive income. Cost of sales also includes the cost of manufacturing Korlym, including materials, third-party manufacturing costs and indirect personnel and other overhead costs, based on the number of Korlym tablets for which we recognize revenue, as well as costs of stability testing, logistics and distribution. We classify inventory we do not expect to sell or use in clinical studies within 12 months of the balance sheet date as strategic inventory, a non-current asset.
Net Product Revenue	Net Product Revenue We sell Korlym directly to patients through a single specialty pharmacy. We also sell Korlym to a specialty distributor (“SD”), for which we recognize revenue at the time the SD receives Korlym. SD sales were less than one percent of our net revenue in the years ended December 31, 2020, 2019 and 2018. To determine our revenue from the sale of Korlym, we (i) identify our contract with each customer; (ii) identify the obligations of Corcept and the customer under the contract; (iii) determine the contracted transaction price; (iv) allocate the transaction price to the contract’s performance obligations, which in our case consists of delivering Korlym to the customer; and (v) recognize revenue once Korlym has been delivered, provided we deem it probable that we will collect the payment due to us. Confirmation of coverage by private or government insurance or by a third-party charity is a prerequisite for selling Korlym to a patient. To determine net product revenue, we deduct from sales the cost of our patient co-pay assistance program and our estimates of (a) government chargebacks and rebates, (b) discounts provided to our SD for prompt payment and (c) reserves for expected Korlym returns. We record these estimates at the time we recognize revenue and update them as new information becomes available. Our estimates take into account our understanding of the range of possible outcomes. If results differ from our estimates, we adjust our estimates, causing a change to our net product revenue and earnings. We report any changes in the period they become known, even if they concern transactions occurring in prior periods. Government Rebates: Korlym is eligible for purchase by, or qualifies for reimbursement from, Medicaid and other government programs that are eligible for rebates on the price they pay for Korlym. To determine the appropriate amount to reserve against these rebates, we identify Korlym sold to patients covered by government-funded programs, apply the applicable government discount to these sales, then estimate the portion of total rebates we expect will be claimed. Chargebacks. Although we sell Korlym to the SD at full price, some of the government entities to which the SD sells receive a discount. As it makes such sales, SD recovers the full amount of any related discounts by reducing its payment to us (this reduction is called a “chargeback”). Chargebacks sometimes relate to Korlym purchased by the SD in prior periods. We deduct from our revenue in each period chargebacks claimed by the SD for Korlym it purchased in that period. We also create each period a reserve for chargebacks we estimate the SD will claim in future periods against Korlym it has not yet resold. We determine the amount of this reserve based on our experience with SD chargebacks and our understanding of the SD’s customer base and business practices. We then deduct this reserve from revenue and include in accrued expenses on our consolidated balance sheet a current liability of equal amount. Patient Assistance Program and Charitable Support: It is our policy that no patient be denied Korlym due to inability to pay. We provide financial assistance to eligible patients whose insurance policies have high deductibles or co-payments and deduct the amount of such assistance from gross revenue. We determine the assistance we provide each patient by applying our program guidelines to that patient’s financial position and their insurance policy’s co-payment and deductible requirements for the purchase of Korlym. We donate cash to charities that help patients with financial need pay for the treatment of Cushing’s syndrome. We do not include payments from these charities in revenue, but as a deduction to selling, general and administrative expenses. We provide Korlym at no cost to uninsured patients who do not qualify for charitable support. Sales Returns: Federal law prohibits the return of Korlym sold to patients. Sales to our SD are subject to return. We deduct the amount of Korlym we estimate the SD will return from each period’s gross revenue. We base our estimates on quantitative and qualitative information including, but not limited to, historical return rates, the amount of Korlym held by the SD and projected demand. If we cannot reasonably estimate returns with respect to a particular sale, we defer recognition of revenue until we can make a reasonable estimate. To date, returns have not been significant.
Leases	Leases We determine whether an arrangement contains a lease at inception. A contract is or contains a lease if the contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. To determine whether a contract is or contains a lease, we consider all relevant facts and circumstances to assess whether the customer has the right to both (i) obtain substantially all of the economic benefits from use of the identified asset and (ii) direct the use of the identified asset. We recognize right-of-use assets and lease liabilities at lease commencement. We measure lease liabilities based on the present value of lease payments over the lease term discounted using the rate equal to the rate we would pay on a loan with monthly payments and a term equal to the monthly payments and remaining term of our lease. We estimate our incremental borrowing rate based on non-tender bank quotes and an analysis of public companies with debt and credit carrying terms similar to our lease term. We do not include in the lease term options to extend or terminate the lease unless it is reasonably certain at commencement that we will exercise any such options. We account for the lease components separately from non-lease components for our operating leases. We measure right-of-use assets based on the corresponding lease liabilities adjusted for (i) prepayments made to the lessor at or before the commencement date, (ii) initial direct costs we incur, and (iii) tenant incentives under the lease. We evaluate the recoverability of our right-of-use assets for possible impairment in accordance with our long-lived assets policy. We do not recognize right-of-use assets or lease liabilities for leases with a term of twelve months or less; rather, we recognize the associated lease payments in the consolidated statements of comprehensive income on a straight-line basis over the lease term. Operating leases are reflected on our consolidated balance sheets as operating lease right-of-use assets, short-term operating lease liabilities and long-term operating lease liabilities. We begin recognizing operating lease expense when the lessor makes the underlying asset available to us. We recognize operating lease expense under our operating leases on a straight-line basis. Variable lease payments are expensed as incurred. The Company did not have any finance leases at either December 31, 2020 or 2019.
Research and Development	Research and Development Research and development expenses include the direct cost of discovering and screening new compounds, pre-clinical studies, clinical trials, manufacturing development, submissions to regulatory agencies and related overhead costs. We expense nonrefundable payments and the cost of technologies and materials used in research and development as we incur them. We base our accruals for discovery research, preclinical studies and clinical trials on our estimates of work completed, milestones achieved, patient enrollment and past experience with similar activities. Our estimates include assessments of information from contract research organizations and the status of our own research, development and administrative activities.
Segment Reporting	Segment Reporting We determine our operating segments based on the way we organize our business, make decisions and assess performance. We have only one operating segment, which is the discovery, development and commercialization of pharmaceutical products.
Stock-Based Compensation	Stock-Based Compensation We account for stock-based compensation under the fair value method, based on the value of the award at the grant date. To date, our stock-based compensation has consisted entirely of option grants, which we value using the Black-Scholes model. We recognize stock-based compensation expense over the applicable vesting period, net of estimated forfeitures. If actual forfeitures differ from our estimates, we adjust stock-based compensation expense accordingly.
Income Taxes	Income Taxes We account for income taxes in accordance with ASC 740, Income Taxes (“ASC 740”), which requires recognition of deferred tax assets and liabilities for the expected tax consequences of our future financial and operating activities. Under ASC 740, we determine deferred tax assets and liabilities based on the temporary difference between the financial statement and tax bases of assets and liabilities using the tax rates in effect for the year in which we expect such differences to reverse. If we determine that it is more likely than not that we will not generate sufficient taxable income to realize the value of some or all of our deferred tax assets (net of our deferred tax liabilities), we establish a valuation allowance offsetting the amount we do not expect to realize. We perform this analysis each reporting period and reduce our measurement of deferred taxes, if the likelihood we will realize them becomes uncertain. The deferred tax assets we record each period depend primarily on our ability to generate future taxable income in the United States. Each period, we evaluate the need for a valuation allowance against our deferred tax assets and, if necessary, adjust the valuation allowance so that net deferred tax assets are recorded only to the extent we conclude it is more likely than not that these deferred tax assets will be realized. If our outlook for future taxable income changes significantly, our assessment of the need for, and the amount of, a valuation allowance may also change. We are also required to evaluate and quantify other sources of taxable income, such as the possible reversal of future deferred tax liabilities, should any arise, and the implementation of tax planning strategies. Evaluating and quantifying these amounts is difficult and involves significant judgment, based on all of the available evidence and assumptions about our future activities. We account for uncertain tax positions in accordance with ASC 740, which requires us to adjust our consolidated financial statements to reflect only those tax positions that are more-likely-than-not to be sustained upon review by federal or state examiners. We recognize in the consolidated financial statements the largest expected tax benefit that has a greater than 50 percent likelihood of being sustained on examination by the taxing authorities. We report interest and penalties related to unrecognized tax benefits as income tax expenses.
Recently Adopted Accounting Pronouncements and Recently Issued Accounting Pronouncements Not Yet Adopted	Recently Adopted Accounting Pronouncements In June 2016, the FASB issued ASU No. 2016-13, “Financial Instruments-Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments,” which changes the methodology for measuring credit losses on financial instruments and when such losses are recorded. This standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019. We adopted this standard on January 1, 2020 using the modified retrospective approach with the cumulative effect of the adoption recorded as an adjustment to retained earnings. It had no impact on our consolidated financial statements. Recently Issued Accounting Pronouncements Not Yet Adopted In December 2019, the FASB issued ASU No. 2019-12 (ASC Topic 740), “Simplifying the Accounting for Income Taxes.” This standard simplifies accounting for income taxes by removing certain exceptions to the general principles and clarifying existing guidance. This standard will be effective for fiscal years, and interim periods within those years, beginning after December 15, 2020. We will adopt the new standard in the first quarter of 2021. The adoption of this standard is not expected to have a significant impact on our consolidated financial statements.

Basis of Presentation and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Summary of Allowance Activity Included in Trade Receivables Includes Allowance for Doubtful Accounts, Prompt Pay Cash Discounts and Chargebacks

The following table summarizes activity in each of the product revenue allowance and reserve categories for the year ended December 31, 2020:


	Chargebacks		Government Rebates		Total
	(in thousands)
Balance at December 31, 2017:	$	927	$	7,961	$	8,888
Provision recorded during the period	2,687		28,628		31,315
Provision related to prior period sales	—		532		532
Credit or payments made during the period	(3,268)		(25,988)		(29,256)
Balance at December 31, 2018:	346		11,133		11,479
Provision related to current period sales	783		24,374		25,157
Provision related to prior period sales	—		(95)		(95)
Credit or payments made during the period	(852)		(27,203)		(28,055)
Balance at December 31, 2019:	277		8,209		8,486
Provision related to current period sales	519		27,698		28,217
Provision related to prior period sales	(3)		(631)		(634)
Credit or payments made during the period	(630)		(25,864)		(26,494)
Balance at December 31, 2020:	$	163	$	9,412	$	9,575

Available-for-Sale Securities and Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2020

Available For Sale Securities And Fair Value Measurements [Abstract]

Summary of the classification of available-for-sale securities in condensed consolidated balance sheets

The available-for-sale securities in our Consolidated Balance Sheets are as follows:


	Year Ended December 31,
	2020		2019
	(in thousands)
Cash equivalents	$	50,524	$	18,461
Short-term marketable securities	364,506		244,693
Long-term marketable securities	36,196		39,352
Total marketable securities	$	451,226	$	302,506

Schedule of available-for-sale securities

The following table presents our available-for-sale securities grouped by asset type:


	Fair Value Hierarchy Level	December 31, 2020								December 31, 2019
		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
		(in thousands)
Corporate bonds	Level 2	$	96,999	$	74	$	(9)	$	97,064	$	109,780	$	136	$	(6)	$	109,910
Commercial paper	Level 2	139,791		—		—		139,791		41,237		—		—		41,237
Asset-backed securities	Level 2	39,243		15		(1)		39,257		57,195		63		(5)		57,253
Repurchase agreements	Level 2	—		—		—		—		18,000		—		—		18,000
U.S. treasury securities	Level 1	124,461		131		(2)		124,590		75,574		71		—		75,645
Money market funds	Level 1	50,524		—		—		50,524		461		—		—		461
Total Marketable securities		$	451,018	$	220	$	(12)	$	451,226	$	302,247	$	270	$	(11)	$	302,506

Composition of Certain Balance Sheet Items (Tables)

12 Months Ended

Dec. 31, 2020

Balance Sheet Related Disclosures [Abstract]

Schedule of Composition of Inventory

Inventory


	Year Ended December 31,
	2020		2019
	(in thousands)
Raw materials	$	1,685	$	1,389
Work in progress	12,916		10,086
Finished goods	6,556		5,930
Total inventory	21,157		17,405
Less strategic inventory classified as non-current	(16,247)		(11,981)
Total inventory classified as current	$	4,910	$	5,424

Property, Plant and Equipment

Property and Equipment


	Year Ended December 31,
	2020		2019
	(in thousands)
Furniture and equipment	$	810	$	304
Software	1,485		1,541
Leasehold improvements	1,233		533
	3,528		2,378
Less accumulated depreciation	(1,853)		(1,328)
Property and equipment, net of accumulated depreciation	$	1,675	$	1,050

Schedule of Other Accrued Liabilities

Accrued and other liabilities


	Year Ended December 31,
	2020		2019
	(in thousands)
Accrued compensation	$	10,144	$	12,331
Government rebates	9,412		8,209
Accrued selling and marketing costs	665		491
Legal fees	612		1,087
Professional fees	151		367
Other	202		784
Total accrued and other liabilities	$	21,186	$	23,269

Leases (Tables)

12 Months Ended

Dec. 31, 2020

Leases [Abstract]

Schedule of information of leases asset and liabilities

Our right-of-use assets and related lease liabilities were as follows:


	Year Ended December 31,
	2020			2019
	(in thousands)
Cash paid for operating lease liabilities	$	1,840		$	1,551
Right-of-use assets obtained in connection with operating lease obligations	$	775		$	4,913
Weighted-average remaining lease term (years)	15 months			27 months
Weighted-average discount rate	4.8		%	5.0		%

Schedule of Future Minimum Lease Payments under Non-Cancelable Operating Leases

As of December 31, 2020, future minimum lease payments under non-cancelable operating leases were as follows (in thousands):


2021	$	2,109
2022	530
	2,639
Less imputed interest	(88)
Total operating lease liabilities	$	2,551

Preferred Stock and Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2020

Equity [Abstract]

Summary of Shares of Common Stock Reserved for Future Issuance

Shares of common stock reserved for future issuance as of December 31, 2020 are as follows:


Common stock:			(in thousands)
Exercise of outstanding options			24,946
Shares available for grant under stock option plans			9,041
			33,987

Summary of Stock Plan Activity

The following table summarizes all activity under the 2004 Plan and the 2012 Plan:


		Outstanding Options
	Shares Available For Future Grant	Options Shares Subject to Options Outstanding	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life	Aggregate Intrinsic Value
	(in thousands)	(in thousands)			(in years)	(in thousands)
Balance at December 31, 2019	8,624	23,600	$	8.77
Increase in shares authorized for grant	4,582	—
Shares granted	(5,225)	5,225	$	13.84
Shares exercised	—	(2,819)	$	8.97
Shares canceled and forfeited	1,060	(1,060)	$	13.11
Balance at December 31, 2020	9,041	24,946	$	9.62	6.17	$	412,494

Options exercisable at December 31, 2020		17,047	$	7.83	5.09	$	312,481

Options fully vested and expected to vest at December 31, 2020		24,254	$	9.51	6.10	$	403,738

Summary of Weighted-Average Assumptions and Resultant Fair Value-Based Measurements for Options Granted to Employees and Directors

The following table summarizes the weighted-average assumptions and resultant fair value-based measurements for options granted to employees and directors.


	Year Ended December 31,
	2020	2019	2018
Weighted-average assumptions for stock options granted:
Risk-free interest rate	1.20%	2.34%	2.68%
Expected term	6.0 years	6.0 years	5.9 years
Expected volatility of stock price	59.1%	67.4%	67.9%
Dividend rate	0%	0%	0%
Weighted-average grant date fair value-based measurement	$7.55	$7.09	$10.11

Summary of Stock-Based Compensation

The following table presents a summary of stock-based compensation by financial statement classification.


	Year Ended December 31,
	2020		2019		2018
	(in thousands)
Stock-based compensation capitalized in inventory	$	238	$	120	$	87
Cost of sales	66		144		259
Research and development	11,222		9,541		7,012
Selling, general and administrative	22,251		19,628		16,476
Total stock-based compensation	$	33,777	$	29,433	$	23,834

- Definition

Tabular disclosure of an entity's stock, including par or stated value per share, number and dollar amount of share subscriptions, shares authorized, shares issued, shares outstanding, number and dollar amount of shares held in an employee trust, dividend per share, total dividends, share conversion features, par value plus additional paid in capital, the value of treasury stock and other information necessary to a fair presentation, and EPS information. Stock by class includes common, convertible, and preferred stocks which are not redeemable or redeemable solely at the option of the issuer. Includes preferred stock with redemption features that are solely within the control of the issuer and mandatorily redeemable stock if redemption is required to occur only upon liquidation or termination of the reporting entity. If more than one issue is outstanding, state the title of each issue and the corresponding dollar amount; dollar amount of any shares subscribed but unissued and the deduction of subscriptions receivable there from; number of shares authorized, issued, and outstanding.

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+ Details

Net Income Per Share (Tables)

12 Months Ended

Dec. 31, 2020

Earnings Per Share [Abstract]

Schedule of Computation of Net Income Per Share

The following table shows the computation of net income per share for each period:


	Year Ended December 31,
	2020		2019		2018
	(in thousands, except per share data)
Numerator:
Net income	$	106,011	$	94,181	$	75,410
Denominator:
Weighted-average shares used to compute basic net income per share	115,412		114,349		115,343
Dilutive effect of employee stock options	8,782		8,217		11,345
Weighted-average shares used to compute diluted net income per share	124,194		122,566		126,688
Net income per share
Basic	$	0.92	$	0.82	$	0.65
Diluted	$	0.85	$	0.77	$	0.60

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Schedule of Income before Income Tax, Domestic and Foreign

The domestic and foreign components of income before income taxes were as follows:


	Year Ended December 31,
	2020		2019		2018
	(in thousands)
Domestic	$	131,634	$	116,676	$	92,153
Foreign	(32)		—		—
Income before income taxes	$	131,602	$	116,676	$	92,153

Schedule of Components of Income Tax (Benefit)

The income tax expense for the year ended December 31, 2020, 2019, and 2018 consisted of the following:


	Year Ended December 31,
	2020		2019		2018
	(in thousands)
U.S. federal taxes:
Current	$	6,094	$	1,716	$	—
Deferred	14,418		15,944		14,243
Total U.S. federal taxes	20,512		17,660		14,243
State taxes:
Current	5,368		3,900		2,676
Deferred	520		935		(176)
Total state taxes	5,888		4,835		2,500
Foreign taxes:
Current	$	41	$	—	$	—
Deferred	$	(850)	$	—	$	—
Total foreign taxes	(809)		—		—
Total	$	25,591	$	22,495	$	16,743

Schedule of Significant Components of Deferred Tax Assets

Significant components of our deferred tax assets are as follows:


	Year Ended December 31,
	2020		2019
Deferred tax assets:	(in thousands)
Federal and state net operating losses	$	5,412	$	7,391
Capitalized research and patent costs	5,139		7,317
Research credits	15,107		26,164
Stock-based compensation costs	14,043		12,026
Operating lease liability	630		857
Other	3,473		4,186
Total deferred tax assets	43,804		57,941
Valuation allowance	(11,581)		(11,410)
Deferred tax liabilities
Operating lease right-of-use asset	(620)		(854)
Total deferred tax liabilities	(620)		(854)
Net deferred tax assets	$	31,603	$	45,677

Schedule of Reconciliation of Statutory Federal Income Tax Rate to Effective Rate

The following table presents a reconciliation from the statutory federal income tax rate to the effective rate.


	Year Ended December 31,
	2020		2019		2018
	(in thousands)
U.S. federal taxes at statutory rate	$	27,636	$	24,502	$	19,354
R&D and other credits	(6,666)		(4,504)		(2,178)
State income taxes	4,651		3,819		1,975
Non-deductible compensation	1,508		657		394
Stock-based compensation	(1,551)		(2,107)		(3,165)
Other	13		128		363
Total	$	25,591	$	22,495	$	16,743

Schedule of Changes in Balance of Gross Unrecognized Tax Benefits

The aggregate annual changes in the balance of gross unrecognized tax benefits are as follows (in thousands):


	Year Ended December 31,
	2020		2019		2018
Beginning Balance	$	6,029	$	4,756	$	4,139
Increase in tax positions for prior years	158		261		—
Decrease in tax positions for prior years	—		—		(135)
Increase in tax positions for current year	1,284		1,012		752
Decrease in tax positions for current year	—		—		—
Ending Balance	$	7,471	$	6,029	$	4,756

Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2020

Quarterly Financial Information Disclosure [Abstract]

Summary of Quarterly Financial Data

The following table is in thousands, except per share amounts:


Quarter Ended	March 31		June 30		September 30		December 31
2020
Product revenue, net	$	93,247	$	88,565	$	86,327	$	85,735
Gross profit on product revenue	91,369		87,331		85,111		84,481
Net income	30,065		28,327		21,625		25,994
Basic net income per share	$	0.26	$	0.25	$	0.19	$	0.22
Diluted net income per share	$	0.25	$	0.23	$	0.17	$	0.20

2019
Product revenue, net	$	64,829	$	72,257	$	81,505	$	87,895
Gross profit on product revenue	63,589		70,880		80,054		86,459
Net income	18,274		20,186		26,340		29,381
Basic net income per share	$	0.16	$	0.18	$	0.23	$	0.26
Diluted net income per share	$	0.15	$	0.17	$	0.22	$	0.24

Basis of Presentation and Summary of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2020 series compound segment	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Line Items]
Number of series of selective cortisol modulators \| series	4
Number of compounds (more than) \| compound	1,000
Number of operating segments \| segment	1
Sales Revenue, Net \| Customer Concentration Risk
Accounting Policies [Line Items]
Percentage of sales to one specialty distributor, less than	1.00%	1.00%	1.00%

Basis of Presentation and Summary of Significant Accounting Policies (Summary of Allowance Activity Included in Trade Receivables Includes Allowance for Doubtful Accounts, Prompt Pay Cash Discounts and Chargebacks) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for Doubtful Accounts Receivable [Roll Forward}
Balance at beginning of period	$ 8,486	$ 11,479	$ 8,888
Provision related to current period sales			31,315
Credit or payments made during the period	(26,494)	(28,055)	(29,256)
Provision related to current period sales	28,217	25,157
Provision related to prior period sales	634	95	532
Balance at end of period	9,575	8,486	11,479
Chargebacks
Allowance for Doubtful Accounts Receivable [Roll Forward}
Balance at beginning of period	277	346	927
Provision related to current period sales			2,687
Credit or payments made during the period	(630)	(852)	(3,268)
Provision related to current period sales	519	783
Provision related to prior period sales	3	0	0
Balance at end of period	163	277	346
Government Rebates
Allowance for Doubtful Accounts Receivable [Roll Forward}
Balance at beginning of period	8,209	11,133	7,961
Provision related to current period sales			28,628
Credit or payments made during the period	(25,864)	(27,203)	(25,988)
Provision related to current period sales	27,698	24,374
Provision related to prior period sales	631	95	532
Balance at end of period	$ 9,412	$ 8,209	$ 11,133

Significant Agreements (Narrative) (Details)		1 Months Ended
Significant Agreements (Narrative) (Details)	Jul. 25, 2018 renewal_option	Aug. 31, 2017	Dec. 31, 2020 USD ($)	Mar. 31, 2020 USD ($)
PCAs
Debt And Credit Agreements [Line Items]
Purchase obligation \| $			$ 0	$ 5,900,000
Optime Care, Inc.
Debt And Credit Agreements [Line Items]
Initial agreement period		5 years
Active Pharmaceutical Ingredient
Debt And Credit Agreements [Line Items]
Number of renewal options \| renewal_option	2
Renewal option period	1 year

Available-for-Sale Securities and Fair Value Measurements - Summary of the classification of available-for-sale securities in condensed consolidated balance sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	$ 451,226	$ 302,506
Cash equivalents
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	50,524	18,461
Short-term marketable securities
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	364,506	244,693
Long-term marketable securities
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	$ 36,196	$ 39,352

Available-for-Sale Securities and Fair Value Measurements - Schedule of Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Estimated Fair Value	$ 451,226	$ 302,506
Estimate of fair value measurement
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	451,018	302,247
Gross Unrealized Gains	220	270
Gross Unrealized Losses	(12)	(11)
Estimated Fair Value	451,226	302,506
Estimate of fair value measurement \| Corporate bonds \| Level 2
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	96,999	109,780
Gross Unrealized Gains	74	136
Gross Unrealized Losses	(9)	(6)
Estimated Fair Value	97,064	109,910
Estimate of fair value measurement \| Commercial paper \| Level 2
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	139,791	41,237
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	139,791	41,237
Estimate of fair value measurement \| Asset-backed securities \| Level 2
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	39,243	57,195
Gross Unrealized Gains	15	63
Gross Unrealized Losses	(1)	(5)
Estimated Fair Value	39,257	57,253
Estimate of fair value measurement \| Repurchase agreements \| Level 2
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	0	18,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	0	18,000
Estimate of fair value measurement \| U.S. treasury securities \| Level 1
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	124,461	75,574
Gross Unrealized Gains	131	71
Gross Unrealized Losses	(2)	0
Estimated Fair Value	124,590	75,645
Estimate of fair value measurement \| Money market funds \| Level 1
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	50,524	461
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	$ 50,524	$ 461

Available-for-Sale Securities and Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest receivable, current	$ 1.3	$ 1.0
Maximum maturity period	2 years
Weighted average maturity period	5 months
Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term marketable securities, remaining maturity	13 months
Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long term marketable securities, remaining maturity	17 months

Composition of Certain Balance Sheet Items (Composition of Inventory) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Raw materials	$ 1,685	$ 1,389
Work in progress	12,916	10,086
Finished goods	6,556	5,930
Total inventory	21,157	17,405
Less strategic inventory classified as non-current	(16,247)	(11,981)
Total inventory classified as current	$ 4,910	$ 5,424

Composition of Certain Balance Sheet Items - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant, and equipment and finance lease right-of-use asset, before accumulated depreciation and amortization	$ 3,528	$ 2,378
Less accumulated depreciation	(1,853)	(1,328)
Property and equipment, net of accumulated depreciation	1,675	1,050
Furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment	810	304
Software
Property, Plant and Equipment [Line Items]
Property and equipment	1,485	1,541
Leasehold improvements
Property, Plant and Equipment [Line Items]
Leasehold improvements	$ 1,233	$ 533

Composition of Certain Balance Sheet Items (Other Accrued Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Accrued compensation	$ 10,144	$ 12,331
Government rebates	9,412	8,209
Accrued selling and marketing costs	665	491
Legal fees	612	1,087
Professional fees	151	367
Other	202	784
Total accrued and other liabilities	$ 21,186	$ 23,269

Composition of Certain Balance Sheet Items (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Balance Sheet Related Disclosures [Abstract]
Deposits for clinical trials	$ 4.8	$ 3.3

Leases - (Details) - USD ($) $ in Thousands	12 Months Ended
Leases - (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2020	Jan. 31, 2019
Lessee, Lease, Description [Line Items]
Operating lease right-of-use asset	$ 2,509	$ 3,446
Total operating lease liabilities	2,551
Operating lease expense	$ 1,900	$ 1,500
Operating leases, rent expense			$ 1,300
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Operating lease right-of-use asset				$ 800	$ 1,900
Total operating lease liabilities				$ 800	$ 1,900

Leases - Right-of-use Assets and Related Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Cash paid for operating lease liabilities	$ 1,840	$ 1,551
Right-of-use assets obtained in connection with operating lease obligations	$ 775	$ 4,913
Weighted-average remaining lease term (years)	15 months	27 months
Weighted-average discount rate	4.80%	5.00%

Leases - Future Minimum Lease Payments (Details) $ in Thousands	Dec. 31, 2020 USD ($)
Leases [Abstract]
2021	$ 2,109
2022	530
Payments due	2,639
Less imputed interest	(88)
Total operating lease liabilities	$ 2,551

Related Party Transactions (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Feb. 26, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Shareholders Equity [Line Items]
Aggregate purchase price		$ 9,945	$ 30,975	$ 23,657
Chief Executive Officer
Shareholders Equity [Line Items]
Aggregate purchase price	$ 300
Cost per share (in dollars per share)	$ 13.54

Preferred Stock and Stockholders' Equity (Narrative) (Details)		12 Months Ended
	Feb. 04, 2021 shares	Dec. 31, 2020 USD ($) stock_option_plan $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) shares	Nov. 03, 2020 USD ($)	Dec. 31, 2012 shares
Shareholders Equity [Line Items]
Preferred stock, shares authorized (in shares)		10,000,000	10,000,000
Preferred stock, par value (in dollars per share) \| $ / shares		$ 0.001	$ 0.001
Preferred stock, shares outstanding (in shares)		0	0
Aggregate purchase price \| $		$ 9,945,000	$ 30,975,000	$ 23,657,000
Issuance of common stock upon exercise of options (in shares)		2,819,000	2,900,000	2,100,000
Increase in shares authorized for grant (in shares)		4,582,000
Number of stock option plans \| stock_option_plan		2
Shares available for future grants (in shares)		9,041,000	8,624,000
Total intrinsic value of options exercised \| $		$ 28,800,000	$ 26,600,000	$ 26,600,000
Fair value of options vested \| $		$ 34,000,000.0	$ 30,200,000	$ 22,600,000
Stock options outstanding (in shares)		24,946,000	23,600,000	22,800,000
Employee and Director Stock Option
Shareholders Equity [Line Items]
Unrecognized compensation expense \| $		$ 54,800,000
Unrecognized compensation expense, weighted-average vesting period		2 years 4 months 20 days
2012 Equity Incentive Award Plan
Shareholders Equity [Line Items]
Increase in shares available for issuance based on percentage of common stock outstanding		4.00%
Exercise price as percentage of fair value of common stock, no less than		100.00%
Shares available for future grants (in shares)						5,300,000
Expiration period		10 years
2012 Equity Incentive Award Plan \| Minimum
Shareholders Equity [Line Items]
Stock options, vesting period		1 year
2012 Equity Incentive Award Plan \| Maximum
Shareholders Equity [Line Items]
Stock options, vesting period		4 years
2004 Equity Incentive Plan
Shareholders Equity [Line Items]
Exercise price as percentage of fair value of common stock, no less than		100.00%
2004 Equity Incentive Plan \| Minimum
Shareholders Equity [Line Items]
Stock options, vesting period		1 year
2004 Equity Incentive Plan \| Maximum
Shareholders Equity [Line Items]
Stock options, vesting period		5 years
Common Stock \| Stock Repurchase Program
Shareholders Equity [Line Items]
Authorized amount \| $					$ 200,000,000
Shares repurchased (in shares)		500,000	2,800,000	1,800,000
Aggregate purchase price \| $		$ 9,700,000	$ 31,000,000.0	$ 23,700,000
Cost per share (in dollars per share) \| $ / shares		$ 21.08
Common Stock
Shareholders Equity [Line Items]
Shares repurchased (in shares)		479,000	2,780,000	1,807,000
Issuance of common stock upon exercise of options (in shares)		2,819,000	2,929,000	2,121,000
Subsequent event \| 2012 Equity Incentive Award Plan
Shareholders Equity [Line Items]
Increase in shares authorized for grant (in shares)	4,700,000

Preferred Stock and Stockholders' Equity (Shares of Common Stock Reserved for Future Issuance) (Details) shares in Thousands	Dec. 31, 2020 shares
Shareholders Equity [Line Items]
Shares of common stock reserved for future issuance (in shares)	33,987
Stock Options Outstanding
Shareholders Equity [Line Items]
Shares of common stock reserved for future issuance (in shares)	24,946
Shares Available For Grant Under Stock Option Plans
Shareholders Equity [Line Items]
Shares of common stock reserved for future issuance (in shares)	9,041

Preferred Stock and Stockholders' Equity (Summary of Stock Plan Activity) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Shares Available For Future Grant
Beginning balance (in shares)	8,624
Increase in shares authorized for grant (in shares)	4,582
Shares granted (in shares)	(5,225)
Shares canceled and forfeited (in shares)	1,060
Ending balance (in shares)	9,041	8,624
Shares Subject to Options Outstanding
Beginning balance (in shares)	23,600	22,800
Shares granted (in shares)	5,225
Shares exercised (in shares)	(2,819)	(2,900)	(2,100)
Shares canceled and forfeited (in shares)	(1,060)
Ending balance (in shares)	24,946	23,600	22,800
Options exercisable (in shares)	17,047
Options fully vested and expected to vest (in shares)	24,254
Outstanding Options, Weighted- Average Exercise Price
Beginning balance (in dollars per share)	$ 8.77
Shares granted (in dollars per share)	13.84
Shares exercised (in dollars per share)	8.97
Shares canceled and forfeited (in dollars per share)	13.11
Ending balance (in dollars per share)	9.62	$ 8.77
Options exercisable (in dollars per share)	7.83
Options fully vested and expected to vest (in dollars per share)	$ 9.51
Outstanding Options, Weighted Average Remaining Contractual Life
Weighted average remaining contractual life	6 years 2 months 1 day
Weighted average remaining contractual life, Options exercisable	5 years 1 month 2 days
Weighted average remaining contractual life, Options fully vested and expected to vest	6 years 1 month 6 days
Outstanding Options, Aggregate Intrinsic Value
Aggregate Intrinsic Value	$ 412,494
Options exercisable	312,481
Options fully vested and expected to vest	$ 403,738

Preferred Stock and Stockholders' Equity (Summary of Weighted-Average Assumptions and Resultant Fair Value-Based Measurements for Options Granted to Employees and Directors) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Weighted-average assumptions for stock options granted:
Risk-free interest rate	1.20%	2.34%	2.68%
Expected term	6 years	6 years	5 years 10 months 24 days
Expected volatility of stock price	59.10%	67.40%	67.90%
Dividend rate	0.00%	0.00%	0.00%
Weighted-average grant date fair value-based measurement (in dollars per share)	$ 7.55	$ 7.09	$ 10.11

Preferred Stock and Stockholders' Equity (Summary of Stock-Based Compensation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation capitalized in inventory	$ 238	$ 120	$ 87
Total stock-based compensation	33,777	29,433	23,834
Cost of sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	66	144	259
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	11,222	9,541	7,012
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 22,251	$ 19,628	$ 16,476

Net Income Per Share (Schedule of Computation of Net Income) (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Numerator:
Net income	$ 25,994	$ 21,625	$ 28,327	$ 30,065	$ 29,381	$ 26,340	$ 20,186	$ 18,274	$ 106,011	$ 94,181	$ 75,410
Denominator:
Weighted-average shares used to compute basic net income per share (in shares)									115,412	114,349	115,343
Dilutive effect of employee stock options (in shares)									8,782	8,217	11,345
Weighted-average shares used to compute diluted net income per share (in shares)									124,194	122,566	126,688
Net income per share
Basic (in dollars per share)	$ 0.22	$ 0.19	$ 0.25	$ 0.26	$ 0.26	$ 0.23	$ 0.18	$ 0.16	$ 0.92	$ 0.82	$ 0.65
Diluted (in dollars per share)	$ 0.20	$ 0.17	$ 0.23	$ 0.25	$ 0.24	$ 0.22	$ 0.17	$ 0.15	$ 0.85	$ 0.77	$ 0.60

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

Net Income Per Share (Details) - shares shares in Thousands	12 Months Ended
Net Income Per Share (Details) - shares shares in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options outstanding (in shares)	24,946	23,600	22,800
Stock Options to Purchase Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average options excluded from the computation of diluted net income per share (in shares)	11,200	9,900	5,000

Income Taxes - Schedule of Components of income Tax (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Domestic	$ 131,634	$ 116,676	$ 92,153
Foreign	(32)	0	0
Income before income taxes	$ 131,602	$ 116,676	$ 92,153

Income Taxes (Components of Income Tax (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
U.S. federal taxes:
Current	$ 6,094	$ 1,716	$ 0
Deferred	14,418	15,944	14,243
Total U.S. federal taxes	20,512	17,660	14,243
State taxes:
Current	5,368	3,900	2,676
Deferred	520	935	(176)
Total state taxes	5,888	4,835	2,500
Foreign taxes:
Current	41	0	0
Deferred	(850)	0	0
Total foreign taxes	(809)	0	0
Total	$ 25,591	$ 22,495	$ 16,743

Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
Income Taxes (Narrative) (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Increase (decrease) in valuation allowance	$ 200,000	$ 200,000	$ (1,300,000)
Unrecognized tax benefits	7,471,000	6,029,000	4,756,000	$ 4,139,000
Unrecognized tax benefits that would impact effective tax rate	6,100,000
Unrecognized tax benefits that would be offset by a change in valuation allowance		1,400,000
Unrecognized tax benefits, accrued interest	0	0	0
Unrecognized tax benefits, accrued penalties	0	$ 0	$ 0
California State
Income Taxes [Line Items]
Net operating loss carryforwards	75,200,000
Research and development tax credits	8,500,000
Other States
Income Taxes [Line Items]
Net operating loss carryforwards	2,900,000
Research and development tax credit \| Federal
Income Taxes [Line Items]
Research and development tax credits	6,800,000
Orphan drug tax credit \| Federal
Income Taxes [Line Items]
Research and development tax credits	$ 7,800,000

Income Taxes (Significant Components of Deferred Tax Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Federal and state net operating losses	$ 5,412	$ 7,391
Capitalized research and patent costs	5,139	7,317
Research credits	15,107	26,164
Stock-based compensation costs	14,043	12,026
Operating lease liability	630	857
Other	3,473	4,186
Total deferred tax assets	43,804	57,941
Valuation allowance	(11,581)	(11,410)
Deferred tax liabilities
Operating lease right-of-use asset	(620)	(854)
Total deferred tax liabilities	(620)	(854)
Net deferred tax assets	$ 31,603	$ 45,677

Income Taxes (Reconciliation of Statutory Federal Income Tax Rate to Effective Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
U.S. federal taxes at statutory rate	$ 27,636	$ 24,502	$ 19,354
R&D and other credits	(6,666)	(4,504)	(2,178)
State income taxes	4,651	3,819	1,975
Non-deductible compensation	1,508	657	394
Stock-based compensation	(1,551)	(2,107)	(3,165)
Other	13	128	363
Total	$ 25,591	$ 22,495	$ 16,743

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Income Taxes (Changes in Balance of Gross Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	$ 6,029	$ 4,756	$ 4,139
Increase in tax positions for prior years	158	261	0
Decrease in tax positions for prior years	0	0	(135)
Increase in tax positions for current year	1,284	1,012	752
Decrease in tax positions for current year	0	0	0
Ending Balance	$ 7,471	$ 6,029	$ 4,756

Commitments and contingencies (Narratives) (Details)	1 Months Ended	12 Months Ended
Commitments and contingencies (Narratives) (Details)	Mar. 31, 2020 USD ($) kg	Dec. 31, 2020 USD ($)
Commitment And Contingencies [Line Items]
Short-term purchase commitment, minimum mass required \| kg	400
Losses for contingent liability		$ 0
Provision for a loss contingency		0
PCAs
Commitment And Contingencies [Line Items]
Purchase obligation	$ 5,900,000	$ 0

Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Product revenue, net	$ 85,735	$ 86,327	$ 88,565	$ 93,247	$ 87,895	$ 81,505	$ 72,257	$ 64,829	$ 353,874	$ 306,486	$ 251,247
Gross profit on product revenue	84,481	85,111	87,331	91,369	86,459	80,054	70,880	63,589
Net income	$ 25,994	$ 21,625	$ 28,327	$ 30,065	$ 29,381	$ 26,340	$ 20,186	$ 18,274	$ 106,011	$ 94,181	$ 75,410
Basic net income per share (in dollars per share)	$ 0.22	$ 0.19	$ 0.25	$ 0.26	$ 0.26	$ 0.23	$ 0.18	$ 0.16	$ 0.92	$ 0.82	$ 0.65
Diluted net income per share (in dollars per share)	$ 0.20	$ 0.17	$ 0.23	$ 0.25	$ 0.24	$ 0.22	$ 0.17	$ 0.15	$ 0.85	$ 0.77	$ 0.60

- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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