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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2018	Feb. 20, 2019	Jun. 30, 2018
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Trading Symbol	CORT
Entity Registrant Name	CORCEPT THERAPEUTICS INC
Entity Central Index Key	0001088856
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Public Float			$ 1,553,404,064
Entity Common Stock, Shares Outstanding		114,723,281

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 41,625	$ 31,062
Short-term marketable securities	165,135	57,682
Trade receivables, net of allowances	17,588	15,300
Other receivable	0	12,896
Inventory	4,732	4,576
Prepaid expenses and other current assets	7,740	2,669
Total current assets	236,820	124,185
Strategic inventory	11,510	3,800
Property and equipment, net of accumulated depreciation	655	518
Long-term marketable securities	0	15,281
Other assets	50	50
Deferred tax assets, net	62,659	76,703
Total assets	311,694	220,537
Current liabilities:
Accounts payable	8,266	8,579
Accrued clinical expenses	3,521	2,247
Other accrued liabilities	23,786	18,743
Total current liabilities	35,573	29,569
Long-term accrued income taxes	239	0
Total liabilities	35,812	29,569
Commitments and contingencies (Note 11)
Stockholders’ equity:
Preferred stock, par value $0.001 per share, 10,000 shares authorized and no shares outstanding at December 31, 2018 and December 31, 2017	0	0
Common stock, par value $0.001 per share, 280,000 shares authorized and 116,838 issued and 115,031 outstanding at December 31, 2018 and 114,717 shares issued and outstanding at December 31, 2017	117	115
Additional paid-in capital	417,228	384,074
Treasury stock; at cost; 1,807 shares of common stock at December 31, 2018; no shares of common stock at December 31, 2017	(23,657)	0
Accumulated other comprehensive loss	(70)	(75)
Accumulated deficit	(117,736)	(193,146)
Total stockholders’ equity	275,882	190,968
Total liabilities and stockholders’ equity	$ 311,694	$ 220,537

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
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)	116,838,000	114,717,000
Common stock, shares outstanding (in shares)	115,031,000	114,717,000
Treasury stock (in shares)	1,807,000	0

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Product revenue, net	$ 251,247,000	$ 159,201,000	$ 81,321,000
Operating expenses:
Cost of sales	5,215,000	3,554,000	2,058,000
Research and development	75,247,000	40,376,000	23,844,000
Selling, general and administrative	81,289,000	62,416,000	45,240,000
Total operating expenses	161,751,000	106,346,000	71,142,000
Income from operations	89,496,000	52,855,000	10,179,000
Interest and other income (expense)	2,657,000	(49,000)	(2,039,000)
Income before income taxes	92,153,000	52,806,000	8,140,000
Income tax expense (benefit)	16,743,000	(76,316,000)	0
Net income	75,410,000	129,122,000	8,140,000
Other comprehensive income (loss):
Net unrealized gain (loss) on available-for-sale investments, net of tax impact of $22, $0 and $0, respectively	5,000	(75,000)	0
Total comprehensive income	$ 75,415,000	$ 129,047,000	$ 8,140,000
Basic net income per share (in dollars per share)	$ 0.65	$ 1.14	$ 0.07
Diluted net income per share (in dollars per share)	$ 0.60	$ 1.04	$ 0.07
Weighted average shares outstanding used in computing net income per share
Basic (in shares)	115,343	113,527	110,566
Diluted (in shares)	126,688	124,515	116,139

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net unrealized gain (loss) on available-for-sale investments, tax	$ 22	$ 0	$ 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 Loss	Accumulated Deficit
Beginning Balance at Dec. 31, 2015	$ 18,498			$ 110	$ 348,796			$ 0	$ 0	$ (330,408)
Beginning Balance (in shares) at Dec. 31, 2015				109,642
Issuance of common stock upon exercise of options	$ 7,683			$ 3	7,680
Issuance of common stock upon exercise of options (in shares)	3,068			3,068
Stock-based compensation		$ 7,002	$ 56			$ 7,002	$ 56
Net income	$ 8,140									8,140
Ending Balance at Dec. 31, 2016	41,379			$ 113	363,534			0	0	(322,268)
Ending Balance (in shares) at Dec. 31, 2016				112,710
Issuance of common stock upon exercise of options	$ 7,181			$ 2	7,179
Issuance of common stock upon exercise of options (in shares)	2,007			2,007
Stock-based compensation		13,330	$ 31			13,330	$ 31
Net unrealized loss on marketable securities, net of tax	$ (75)								(75)
Net income	129,122									129,122
Ending Balance at Dec. 31, 2017	190,968			$ 115	384,074				(75)	(193,146)
Ending Balance (in shares) at Dec. 31, 2017				114,717
Issuance of common stock upon exercise of options	$ 9,322			$ 2	9,320
Issuance of common stock upon exercise of options (in shares)	2,121			2,121
Stock-based compensation		$ 23,834				$ 23,834
Net unrealized loss on marketable securities, net of tax	$ 5								5
Purchases of treasury stock	(23,657)							(23,657)
Purchases of treasury stock (in shares)				(1,807)
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

- Definition

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

+ References + Details

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 75,410	$ 129,122	$ 8,140
Adjustments to reconcile net income to net cash provided by operations:
Stock-based compensation	23,747	13,361	7,058
Accretion of interest (income) expense	(1,721)	456	1,929
Amortization of debt financing costs	0	14	21
Deferred income taxes	14,067	(76,703)	0
Excess tax benefits from stock option activity	0	293	0
Depreciation and amortization of property and equipment	236	106	87
Changes in operating assets and liabilities:
Trade receivables	(2,288)	(5,440)	(3,639)
Other receivable	12,896	(12,896)	0
Inventory	(7,779)	(2,262)	(682)
Prepaid expenses and other current assets	(5,071)	(705)	(1,322)
Other assets	0	(26)	0
Accounts payable	(389)	6,289	965
Accrued clinical expenses	1,274	780	296
Other accrued liabilities	5,044	8,546	5,696
Deferred revenue	0	0	(158)
Long-term accrued income taxes	239	0	0
Net cash provided by operating activities	115,665	60,935	18,391
Cash flows from investing activities:
Purchases of property and equipment	(298)	(419)	(194)
Proceeds from maturities of marketable securities	142,655	29,950	0
Purchases of marketable securities	(233,124)	(102,987)	0
Net cash used in investing activities	(90,767)	(73,456)	(194)
Cash flows from financing activities:
Proceeds from exercise of stock options, net of issuance costs	9,322	7,181	7,683
Repurchase of common stock	(23,657)	0	0
Payments related to debt obligation	0	(15,134)	(14,779)
Net cash used in financing activities	(14,335)	(7,953)	(7,096)
Net increase (decrease) in cash and cash equivalents	10,563	(20,474)	11,101
Cash and cash equivalents, at beginning of period	31,062	51,536	40,435
Cash and cash equivalents, at end of period	41,625	31,062	51,536
Supplemental disclosure:
Income taxes paid	$ 1,351	$ 377	$ 40

Basis of Presentation and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Basis of Presentation and Summary of Significant Accounting Policies

Description of Business and Basis of Presentation

Corcept Therapeutics Incorporated was incorporated in the State of Delaware in May 1998, and our headquarters are in Menlo Park, California. We are a commercial-stage pharmaceutical engaged in the discovery, development and commercialization of medications that treat severe metabolic, oncologic and psychiatric disorders by modulating the effect of the stress hormone cortisol. In 2012, the United States Food and Drug Administration (“FDA”) approved our first product, Korlym^® (“mifepristone”) 300 mg tablets, as a once-daily oral medication for 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 three structurally distinct series of selective cortisol modulators, consisting of more than 500 compounds, and are developing compounds from these series as potential treatments for a broad range of serious disorders.

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. This entity has entered into no material financial transactions and has no assets or liabilities.

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 at the time we purchase them will mature in three months or less 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 U.S. Treasury securities, commercial paper, corporate notes, asset-backed securities 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 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 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 concentration of risk in regard to the manufacture of our product. As of December 31, 2018, we had one tablet manufacturer for Korlym - Alcami Corporation (formerly known as AAI Pharma Services Corp.). In addition, we have a single-source manufacturer of mifepristone, the active pharmaceutical ingredient (API), in Korlym - Produits Chimiques Auxiliaires et de Synthèse SA (PCAS). If either of these companies is unable or unwilling to manufacture API or Korlym tablets in the quantities and time frame required, we may not be able to manufacture our product in a timely manner. In order to mitigate these risks, we purchased and hold in inventory additional quantities of mifepristone API and Korlym tablets.

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. Accordingly, our receivables risk is spread among various third-party payors - pharmacy benefit managers, insurance companies, private charities, government programs - and individual patients. We extend credit to third-party payors 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 write down inventory that has become obsolete or has a cost basis in excess of its expected net realizable value. We destroy expired inventory. We recognize the cost of any inventory write down or destruction in cost of sales for that period.

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.

Debt Obligation

Under an agreement with Biopharma (the “Biopharma Financing Agreement” or the “Financing Agreement”), we made payments each quarter equal to 20 percent of our Korlym sales in the quarter. Accounting for the Financing Agreement required us to estimate the amount of each future quarterly payment and the accretion of interest expense. We extinguished our obligations under the Financing Agreement in July 2017. No further payments are due.

See Note 5, Debt Obligation, for additional information regarding this agreement.

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, 2018 and December 31, 2017.

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. 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, 2018:



	Chargebacks			Government Rebates			Total
	(in thousands)
Balance at December 31, 2015:	$	136		$	1,663		$	1,799
Provision recorded during the period	2,081			9,089			11,170
Credit or payments made during the period	(1,749		)	(7,325		)	(9,074		)
Balance at December 31, 2016:	468			3,427			3,895
Provision recorded during the period	2,637			18,097			20,734
Credit or payments made during the period	(2,178		)	(13,563		)	(15,741		)
Balance at December 31, 2017:	927			7,961			8,888
Provision related to current period sales	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

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.

We recognize the expense of options granted to non-employees based on their fair value at the time of vesting.

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 the Company records each period depend primarily on the Company’s ability to generate future taxable income in the United States. Each period, the Company evaluates the need for a valuation allowance for its deferred tax assets and, if necessary, adjusts the valuation allowance so that net deferred tax assets are recorded only to the extent the Company concludes it is more likely than not that these deferred tax assets will be realized. If the Company’s outlook for future taxable income changes significantly, the Company’s 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 also 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 may recognize a tax benefit only if it is more likely than not the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the consolidated financial statements from such positions are then measured based on the largest benefit that has a greater than 50% likelihood of being realized upon settlement. Our policy is to report interest and penalties related to unrecognized tax benefits as income tax expenses.

Recently Adopted Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, “Revenue from Contracts with Customers,” which changes the way companies recognize revenue. This ASU supersedes the revenue recognition requirements in ASC Topic 605, Revenue Recognition and creates a new Topic 606, “Revenue from Contracts with Customers.” Topic 606 applies to all contracts with customers.

We conducted our analysis using the “portfolio of contracts” approach, which permits us to analyze as a group all contracts with similar characteristics. We have two customer groups: patients covered by insurance and the SD. We evaluated the contracts with customers governing our sales and reviewed the related disclosures, policies and controls, which we updated as necessary. Because some of our customer contracts are subject to rebates, chargebacks, discounts, co-pay assistance or other deductions (known as “variable consideration”) that affect the price of each transaction, we focused our analysis on the new standard’s impact on transaction prices. We estimated the amount of variable consideration using either the most likely amount or expected value method, as applicable.

Topic 606 requires us to estimate the net price of each Korlym sale, including any variable consideration, and recognize the estimated amount as revenue at the time we deliver Korlym to the customer. On January 1, 2018, we adopted Topic 606 using the modified retrospective approach. Adoption of this standard had no impact on our consolidated financial statements.

In January 2016, the FASB issued Accounting Standards Update No. 2016-01 “Financial Instruments: Recognition and Measurement of Financial Assets and Financial Liabilities.” This update changes accounting for equity investments, financial liabilities under the fair value option, and the presentation and disclosure requirements for financial instruments. In addition, it clarifies guidance regarding recognition of deferred tax assets that result from unrealized losses on available-for-sale debt securities. We adopted this standard on January 1, 2018. It had no impact on our consolidated financial statements.

In August 2016, the FASB issued ASU No. 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments,” which is intended to reduce the existing diversity in practice in how certain cash receipts and cash payments are classified in the statement of cash flows. In November 2016, the FASB issued ASU 2016-18, Statement of Cash Flows, Restricted Cash (Topic 230) (ASU 2016-18), which requires the inclusion of restricted cash with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. ASU 2016-15 and ASU 2016-18 are both effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years, provided that all of the amendments are adopted in the same period. We adopted this standard on January 1, 2018. It had no impact on our consolidated financial statements.

In May 2017, the FASB issued ASU No. 2017-09, Stock Compensation (Topic 718): “Scope of Modification Accounting,” which changes the accounting for modifications to the terms and conditions of share-based payment awards. We adopted this standard on January 1, 2018. It had no impact on our consolidated financial statements.

Recently Issued Accounting Pronouncements Not Yet Adopted

In February 2016, the FASB issued ASU No. 2016-02, “Leases”, which requires lease transactions with terms longer than 12 months to be recognized on the balance sheet as “lease liabilities” and “right-of-use assets.” We adopted this standard using the modified retrospective approach on January 1, 2019. Prior comparative periods will not be adjusted under this approach. We have reviewed all contracts that may contain leases and we have determined that the most significant impact is to our accounting for our leased office space. We have elected to apply the package of practical expedients that allows us to not reassess lease classification for any expired or existing lease contracts. The adoption did not have a material impact on our retained earnings on the adoption date and increased our “lease liabilities and “right-of-use assets” by a range of approximately $1.5 million to $2.5 million. Our evaluation of the new standard consisted of reviewing the related disclosures, policies and controls, which we updated as necessary.

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. Early adoption is permitted beginning after December 15, 2018. We plan to adopt this standard on January 1, 2020. Although we have not concluded our analysis, we do not expect adoption of this standard to have a material impact on our consolidated financial statements.

In February 2018, the FASB issued ASU No. 2018-02, “Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.” The standard allows companies to reclassify to retained earnings tax effects related to items that have been stranded in accumulated other comprehensive income as a result of the Tax Cuts and Jobs Act (the “Act”). An entity that elects to reclassify these amounts must reclassify stranded tax effects related to the Act’s change in US federal tax rate for all items accounted for in other comprehensive income. These entities can also elect to reclassify other stranded effects that relate to the Act but do not directly relate to the change in the federal rate. This standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018. We adopted this standard on January 1, 2019. It had no impact on our consolidated financial statements.

In June 2018, the FASB issued ASU No. 2018-07, “Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting,” which expands the scope of ASC 718 to include all share-based payment arrangements related to the acquisition of goods and services from nonemployees. This standard is effective for fiscal years and interim periods within those years, beginning after December 15, 2018. We adopted this standard on January 1, 2019. It had no impact on our consolidated financial statements.

In August 2018, the FASB issued ASU No. 2018-13, “Fair Value Measurements (Topic 820),” which eliminates or modifies certain disclosure requirements for fair value measurements and requires disclosure of certain new information. This standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019. We plan to adopt this standard on January 1, 2020 and are currently evaluating the impact of this new standard on our consolidated financial statements.

In August 2018, the FASB issued ASU No. 2018-15, “Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract,” which requires a customer that is a party to a cloud computing service contract to follow the internal-use software guidance in ASC 350-40 to determine which implementation costs to defer and recognize as an asset. This standard is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019. We plan to adopt this standard on January 1, 2020 and are currently evaluating the impact of this new standard on our consolidated financial statements.

Significant Agreements	12 Months Ended
Significant Agreements	Dec. 31, 2018
Significant Agreements 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 Active Pharmaceutical Ingredient (API) 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. Tablet Manufacture In April 2014, we entered into a manufacturing agreement with Alcami Corporation for the manufacture and package of Korlym tablets. The initial term of this agreement was three years, with consecutive automatic extensions of two years unless either party gives written notice – in the case of Alcami Corporation, 18 months prior to the end of the applicable term, and in our case 12 months prior to the end of the applicable term – that it does not want such an extension. We may terminate the agreement if Alcami Corporation is unable to manufacture the product for a consecutive four-month period, if the product is withdrawn from the market or for any reason with six months of advanced notice. Research and Development Agreements We have also exclusively licensed from the University of Chicago three United States patents for the use of cortisol modulators in combination with anti-cancer agents to treat patients with triple-negative breast cancer and two United States patents for the use of cortisol modulators in combination with anti-androgen agents to treat patients with CRPC. Pursuant to these licenses, we make annual payments, as well as additional one-time payments upon the achievement of clinical and commercial milestones. We are also obligated to pay royalties on revenue generated by any products covered by these patents. The annual and milestone payments are not material and are creditable against future royalties.

Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value of Financial Instruments

As of December 31, 2018 and 2017, we had invested our financial assets in marketable securities, primarily U.S. Treasury securities, commercial paper, corporate notes, asset-backed securities and repurchase agreements. We measured these funds, which totaled $192.2 million and $87.9 million as of December 31, 2018 and 2017, respectively, at fair value, which approximates cost and classified them as Level 1 and Level 2 assets in the fair value hierarchy.

Our available-for-sale securities included:



	Fair Value	Estimated Fair Value
	Hierarchy Level	December 31, 2018		December 31, 2017
		(in thousands)
Corporate bonds	Level 2	$	54,469	$	26,116
Commercial paper	Level 2	67,906		32,637
Asset-backed securities	Level 2	10,965		—
Repurchase agreements	Level 2	15,000		—
U.S. treasury securities	Level 1	39,287		14,210
Money market funds	Level 1	4,583		14,979
Total Marketable securities		$	192,210	$	87,942

Classified as:
Cash equivalents		$	27,075	$	14,979
Short-term marketable securities		165,135		57,682
Long-term marketable securities		—		15,281
Total marketable securities		$	192,210	$	87,942

The estimated fair value of marketable securities is based on quoted market prices for these or similar investments obtained from a commercial pricing service. The fair value of marketable securities classified within Level 2 is based upon inputs that may include benchmark yields, reported trades, broker/dealer quotes and issuer spreads. Our accumulated other comprehensive loss on our balance sheets consisted of net unrealized losses on available-for-sale investments of $0.1 million at both December 31, 2018 and 2017. We did not recognize any realized gains or losses on sales of investments for any period presented.

As of December 31, 2018, all our marketable securities had original maturities of less than two years. The weighted-average maturity of our holdings was four months. None of our marketable securities changed from one fair value hierarchy to another during the year ended December 31, 2018.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Composition of Certain Balance Sheet Items

12 Months Ended

Dec. 31, 2018

Balance Sheet Related Disclosures [Abstract]

Composition of Certain Balance Sheet Items

Inventory

The composition of inventory was as follows:



	December 31,
	2018			2017
	(in thousands)
Raw materials	$	4,195		$	4,287
Work in progress	5,624			64
Finished goods	6,423			4,025
Total inventory	16,242			8,376
Less strategic inventory classified as non-current	(11,510		)	(3,800		)
Total inventory classified as current	$	4,732		$	4,576

Because we rely on single-source manufacturers of both the active pharmaceutical ingredient (“API”) for Korlym and Korlym tablets, we have purchased significant inventory quantities of these materials. 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

Property and equipment consisted of the following:



	December 31,
	2018			2017
	(in thousands)
Furniture and equipment	$	361		$	188
Software	884			705
Leasehold improvements	35			14
	1,280			907
Less: accumulated depreciation	(625		)	(389		)
	$	655		$	518

Other Accrued Liabilities

Other accrued liabilities consisted of the following:



	December 31,
	2018		2017
	(in thousands)
Government rebates	$	11,132	$	7,961
Accrued compensation	7,879		8,574
Accrued state income taxes	1,542		66
Accrued manufacturing costs	2,032		955
Commercialization costs	261		208
Legal fees	314		276
Professional fees	240		207
Other	386		496
Total other accrued liabilities	$	23,786	$	18,743

Debt Obligation	12 Months Ended
Debt Obligation	Dec. 31, 2018
Debt Disclosure [Abstract]
Debt Obligation	Debt Obligation As discussed in Note 1, Basis of Presentation and Summary of Significant Accounting Policies, Debt Obligation, under the Financing Agreement with Biopharma we borrowed $30.0 million and made payments to Biopharma equal to 20 percent of Korlym sales in that quarter. To secure our obligation, we granted Biopharma a security interest in our patents, trademarks, trade names, domain names, copyrights, know-how, books, records and regulatory approvals related to Korlym and certain other assets and any proceeds from them. Biopharma’s right to receive payments expired in July 2017, when our payments had reached total of $45.0 million. All of our obligations under the Financing Agreement and Biopharma’s security interests in our assets are now extinguished. We recorded no interest expense for the year ended December 31, 2018 and $0.5 million for the year ended December 31, 2017. Total accreted interest for the full term of the Financing Agreement was $15.0 million. We capitalized $0.1 million of issuance costs related to the Financing Agreement, which we amortized over the term of the obligation. At December 31, 2018 and 2017, there were no unamortized issuance costs.

Lease Obligation

12 Months Ended

Dec. 31, 2018

Leases [Abstract]

Lease Obligations

In February 2016, we extended the lease for our office space through 2019 and added more space. In May 2016, we terminated this lease and replaced it with a new one effective to March 31, 2019. In June 2017, we amended that lease to add more space. On November 8, 2018, we amended that lease to add yet more space and extend its term to March 31, 2020. Rent expense for the years ended December 31, 2018, 2017 and 2016 was $1.3 million, $1.1 million and $0.9 million, respectively.

As of December 31, 2018, future minimum lease payments under non-cancelable operating leases were as follows:



	Lease
	Payments
2019	$	1,563
2020	391
Thereafter	—
Total	$	1,954

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions See discussion below in Note 8, Preferred Stock and Stockholders’ Equity, under the caption Common Stock, regarding the sale of securities to various investors, including members of our board of directors and related entities.

Preferred Stock and Stockholders' Equity

12 Months Ended

Dec. 31, 2018

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, 2018 and 2017, we had no outstanding shares of preferred stock.

Common Stock

Significant stock transactions

On August 9, 2018, we announced a program to repurchase up to $100 million of our common stock (the “Stock Repurchase Program”). Unless we terminate or suspend it earlier, the Stock Repurchase Program will remain in effect until June 30, 2019. The timing and amount of any repurchases pursuant to the Stock Repurchase Program will be determined based on market conditions, our stock price and other factors. The Stock Repurchase Program does not require us to acquire any specific number of shares and we may modify, suspended or discontinue it in our sole discretion at any time, without notice. Repurchases may be made through a variety of methods, including in the open market, in block trades, though privately negotiated transactions or accelerated share repurchase transactions or any combination of such methods.

During the year ended December 31, 2018, we repurchased 1.8 million shares of common stock under the Stock Repurchase Program in open market transactions at an average price of $13.09 per share, for an aggregate purchase price of $23.7 million. We have recorded the repurchased shares as treasury stock at cost on our consolidated balance sheet. At December 31, 2018, $76.3 million of the current authorization remained available for the repurchase of shares of our common stock.

We have never declared or paid any dividends.

Shares of common stock reserved for future issuance as of December 31, 2018 are as follows:



Common stock:	(in thousands)
Exercise of outstanding options	22,826
Shares available for grant under stock option plans	7,726
	30,552

On February 8, 2019, our Board of Directors authorized an additional increase of 4.6 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, 2018.

Stock Option Plans

We have two active stock option plans at December 31, 2018 – the 2004 Equity Incentive Plan (the 2004 Plan) and 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 are expected to vest over periods ranging from one 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 2016, 2017 and 2018

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, 2015	8,070		16,195		$	2.98
Increase in shares authorized for grant	4,386		—
Shares granted	(5,906	)	5,906		$	4.92
Shares exercised	—		(3,068	)	$	2.50
Shares cancelled and forfeited	1,370		(1,370	)	$	3.98
Balance at December 31, 2016	7,920		17,663		$	3.63
Increase in shares authorized for grant	4,508		—
Shares granted	(5,282	)	5,282		$	9.90
Shares exercised	—		(2,007	)	$	3.60
Shares cancelled and forfeited	484		(484	)	$	5.04
Balance at December 31, 2017	7,630		20,454		$	5.22
Increase in shares authorized for grant	4,589
Shares granted	(5,599	)	5,599		$	16.27
Shares exercised	—		(2,121	)	$	4.40
Shares cancelled and forfeited	1,106		(1,106	)	$	11.08
Balance at December 31, 2018	7,726		22,826		$	7.72	6.52	$	146,127

Options exercisable at December 31, 2018			14,117		$	4.97	5.25	$	121,434

Options fully vested and expected to vest at December 31, 2018			22,029		$	7.50	6.44	$	144,813

The total intrinsic value of options exercised during the years ended December 31, 2018, 2017 and 2016 was $26.6 million, $22.4 million and $14.8 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 grant date fair value of options to employees and directors that vested during the years ended December 31, 2018, 2017 and 2016 was $22.6 million, $12.3 million and $7.0 million, respectively.

The following is a summary of options outstanding and options exercisable at December 31, 2018.



Options Outstanding											Options Exercisable
Exercise Prices of Options					Number of Shares	Weighted- Average Remaining Contractual Life	Weighted- Average Exercise Price		Aggregate Intrinsic Value		Number of Shares	Weighted- Average Exercise Price		Aggregate Intrinsic Value
					(in thousands)	(in years)			(in thousands)		(in thousands)			(in thousands)
$	0.96	—	$	4.00	9,187	4.6	$	2.83	$	96,713	8,434	$	2.75	$	89,501
$	4.01	—	$	9.00	6,981	6.6	$	6.58	47,366		4,264	$	6.08	31,056
$	9.01	—	$	17.00	5,784	9.1	$	15.10	2,048		1,269	$	14.27	877
$	17.01	—	$	24.29	874	9.1	$	19.41	—		150	$	19.43	—
					22,826	6.5	$	7.72	$	146,127	14,117	$	4.97	$	121,434

The aggregate intrinsic value in the table above represents the total pre-tax intrinsic value that option holders would have received had all option holders exercised their options on December 31, 2018. The aggregate intrinsic value is the difference between our closing stock price on December 31, 2018 and the exercise price, multiplied by the number of options with exercise prices less than the closing stock price on that date.

Stock-Based Compensation related to Employee and Director Options

Assumptions used in determining fair value-based measurements for options 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,
	2018	2017	2016
Weighted-average assumptions for stock options granted:
Risk-free interest rate	2.68%	1.99%	1.31%
Expected term	5.9 years	6.1 years	5.8 years
Expected volatility of stock price	67.9%	68.1%	69.0%
Dividend rate	0%	0%	0%
Weighted-average grant date fair value-based measurement	$10.11	$6.14	$2.98

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. ASC 718 requires us to estimate forfeitures at the time of option grant and revise this estimate in subsequent periods if actual forfeitures differ from our estimates.

Summary of compensation expense related to options to employees and directors

We recognized compensation expense of $23.8 million, $13.4 million and $7.1 million related to options to employees and directors during the years ended December 31, 2018, 2017 and 2016, respectively.

As of December 31, 2018, we had $56.4 million of unrecognized compensation expense for employee and director options outstanding as of that date, which had a weighted-average remaining vesting period of 2.80 years.

Stock Options to Non-Employees

We expense stock-based compensation related to service-based option grants to non-employees on a straight-line basis over the vesting period of the options, which approximates the period over which the related services are rendered, based on the options’ value as calculated by the Black-Scholes option pricing model. In performing this calculation we use the same assumptions as when determining the value of options granted to employees and directors, except that we use the remaining contractual term of the non-employee’s service as the options’ expected term and we recalculate the options’ value each quarter, based on the then current price of our common stock.

We recorded charges to expense for non-employee stock options of zero, $31,000 and $56,000 for the years ended December 31, 2018, 2017 and 2016, respectively.

As of December 31, 2018, there were no awards outstanding to non-employees.

Summary of Stock-based Compensation Expense

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



	Year ended December 31,
	2018		2017		2016
	(in thousands)
Stock-based compensation capitalized in inventory	$	87	$	—	$	—
Cost of sales	259		—		—
Research and development	7,012		3,743		1,312
Selling, general and administrative	16,476		9,618		5,746
Total stock-based compensation	$	23,834	$	13,361	$	7,058

Net Income Per Share

12 Months Ended

Dec. 31, 2018

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 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, including the number of weighted-average shares outstanding.



	Year ended December 31,
	2018		2017		2016
	(in thousands)
Numerator:
Net income	$	75,410	$	129,122	$	8,140
Denominator:
Weighted-average shares used to compute basic net income per share	115,343		113,527		110,566
Dilutive effect of employee stock options	11,345		10,988		5,573
Weighted-average shares used to compute diluted net income per share	126,688		124,515		116,139
Net income per share
Basic	$	0.65	$	1.14	$	0.07
Diluted	$	0.60	$	1.04	$	0.07

On a weighted-average basis, 5.0 million, 1.1 million and 4.4 million stock options outstanding during the years ended December 31, 2018, 2017 and 2016, respectively, were excluded from the computation of diluted net income per share because including them would have reduced dilution.

The following table presents information on securities outstanding as of the end of each period that could potentially dilute the per share data in the future.



	December 31,
	2018	2017	2016
	(in thousands)
Stock options outstanding	22,826	20,454	17,663

Income Taxes

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Income Taxes

The income tax expense (benefit) for the year ended December 31, 2018 and December 31, 2017 consisted of the following:



	Year ended December 31,
	2018			2017
	(in thousands)
U.S. federal taxes:
Current	$	—		$	—
Deferred	14,243			(71,839		)
Total U.S. federal taxes	14,243			(71,839		)
State taxes:
Current	2,676			388
Deferred	(176		)	(4,865		)
Total state taxes	2,500			(4,477		)
Total	$	16,743		$	(76,316	)

There was no income tax benefit or expense for the year ended December 31, 2016. The income tax benefit for the year ended December 31, 2017 resulted primarily from the partial release of our valuation allowance, described more fully below.

The Tax Cuts and Jobs Act of 2017 (“Tax Act”), which became law on December 22, 2017, significantly changed federal income tax law. Among other things, effective January 1, 2018, the new law reduced the corporate income tax rate from 35 percent to 21 percent, repealed the corporate alternative minimum tax, limited some business deductions, modified the maximum deduction of future net operating losses generated with no carryback but an indefinite carryforward provision and extended the compensation deduction limit applicable to certain highly-compensated executives of publicly traded companies to cover additional executive roles.

On December 22, 2017, Staff Accounting Bulletin No. 118 (SAB 118) was issued to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Act. In accordance with SAB 118, the Company recorded a provisional amount related to the remeasurement of certain deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future was a net decrease related to deferred tax assets and deferred tax liabilities of $33.2 million, with a corresponding income tax expense of $33.2 million for the year ended December 31, 2017. As of December 31, 2018, the Company has completed its accounting for the remeasurement of certain deferred tax assets and liabilities based on the rates at which they are expected to reverse in the future. There have been no net changes to the provisional estimates disclosed in the period of enactment under SAB 118.

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:



	December 31,
	2018			2017
Deferred tax assets:	(in thousands)
Federal and state net operating losses	$	23,551		$	41,902
Capitalized research and patent costs	10,260			13,278
Research credits	24,771			22,606
Stock-based compensation costs	9,124			5,596
Other	6,137			5,795
Total deferred tax assets	73,843			89,177
Valuation allowance	(11,184		)	(12,474		)
Net deferred tax assets	$	62,659		$	76,703

Realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Each quarter, we assess our ability to use our deferred tax assets to offset our expected federal and state taxable income based on the weight of all available evidence, including such factors as the history of recent earnings and expected future taxable income on a jurisdiction by jurisdiction basis. In the fourth quarter of 2017, we determined that it was more likely than not that we would generate sufficient taxable income to utilize our federal and state deferred tax assets in every state except California. We therefore included in our balance sheet the net value of all our deferred tax assets except those applicable to California. We maintain a full valuation allowance in relation to California deferred tax assets as of December 31, 2018 because of the uncertainty regarding the realizability of these deferred tax assets. All tax years from Corcept’s inception remain open to examination by the Internal Revenue Service, the California Franchise Tax Board and other state taxing authorities.

The valuation allowance decreased by $1.3 million, $116.9 million and $4.3 million for the years ended December 31, 2018, 2017 and 2016, respectively. The significant decrease in the valuation allowance during 2017 was the result of our release of the entire valuation allowance previously established on our federal and non-California state deferred tax assets.

At December 31, 2018, we had net operating loss carryforwards available to offset any future taxable income that we may generate for federal income tax purposes of $76.8 million, which will begin to expire in the years 2031 through 2036, California net operating loss carryforwards of $69.1 million, which expire in the years 2019 through 2036, and net operating loss carryforwards from other states of $9.4 million, which expire in the years 2023 through 2036.

At December 31, 2018, we also had federal and California research and development tax credits of $21.0 million and $4.6 million, respectively. The federal research credits will begin to expire in the years 2023 through 2038 and the California research credits have no expiration date.

Utilization of our net operating losses and tax credit carryforwards may be subject to substantial annual limitation due to the ownership change limitations provided by the Internal Revenue Code and similar state provisions. Such limitations could result in the expiration of the net operating losses and tax credit carryforwards before utilization.

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



	Year ended December 31,
	2018			2017			2016
	(in thousands)
U.S. federal taxes at statutory rate	$	19,354		$	17,954		$	2,840
Changes in valuation allowance	—			(119,765		)	(3,679		)
Federal tax rate change impact to change in valuation allowance	—			33,233			—
R&D and other credits	(2,178		)	(1,199		)	(69		)
State income taxes	1,975			(2,955		)	—
Non-deductible Compensation	394			33			2,435
Stock-based compensation	(3,165		)	(3,826		)	(1,660		)
Other	363			209			133
Total	$	16,743		$	(76,316	)	$	—

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,
	2018			2017		2016
Beginning Balance	$	4,139		$	3,527	$	4,342
Increase in tax positions for prior years	—			150		222
Decrease in tax positions for prior years	(135		)	—		(1,189		)
Increase in tax positions for current year	752			462		152
Decrease in tax positions for current year	—			—		—
Ending Balance	$	4,756		$	4,139	$	3,527

As of December 31, 2018, 2017 and 2016, the total amount of unrecognized tax benefits was approximately $4.8 million, $4.1 million and $3.5 million, respectively. A valuation allowance is maintained on the tax benefits related to California deferred tax assets and if these tax benefits were recognized it 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, 2018, 2017 and 2016. 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 2018 remain open and subject to tax examination by the appropriate federal or state taxing authorities.

Commitments and contingencies	12 Months Ended
Commitments and contingencies	Dec. 31, 2018
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, CORT118335 and CORT125281. See the discussion in Note 2, Significant Agreements, for further discussion regarding the commitments under these agreements. 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. In August 2017, we terminated our pharmaceutical services agreement with our exclusive specialty pharmacy, Dohmen Life Science Services ("Dohmen") for material breach. In August 2017, Dohmen filed a complaint in the Court of Chancery of the State of Delaware against us alleging unlawful termination and breach of contract and requesting declaratory relief and damages. We filed a complaint against Dohmen in the Superior Court of the State of Delaware and a motion to dismiss the Dohmen complaint against us. In November 2017, we answered Dohmen’s complaint in the Court of Chancery of the State of Delaware and asserted counterclaims against Dohmen. Dohmen refused to transfer to us the cash it collected from $12.9 million in Korlym^® receivables, despite its obligation to do so. As of December 31, 2017, the total amount of these receivables had been included in “Other receivable” on our consolidated balance sheet. In January 2018, we entered into a settlement agreement with Dohmen and mutual release of any and all claims that may have existed between the parties as of that date, pursuant to which Dohmen agreed to deliver to us the cash it had collected from the sale of Korlym on our behalf. The total amount delivered by Dohmen under the settlement agreement was the $12.9 million of Korlym^® receivables described above. No losses and no provision for a loss contingency have been recorded to date.

Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2018

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
2018
Product revenue, net	$	57,659	$	62,312	$	64,445	$	66,831
Gross profit on product revenue	56,485		61,158		63,137		65,252
Net income	17,459		18,196		17,747		22,008
Basic net income per share	0.15		0.16		0.15		0.19
Diluted net income per share	0.14		0.14		0.14		0.18

2017
Product revenue, net	$	27,599	$	35,559	$	42,763	$	53,280
Gross profit on product revenue	26,953		34,784		41,787		52,123
Net income	4,388		12,647		13,757		98,330
Basic net income per share	0.04		0.11		0.12		0.86
Diluted net income per share	0.04		0.10		0.11		0.77

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

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

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

Use of Estimates

Fair Value Measurements

Cash and Cash Equivalents and Marketable Securities

Credit and Concentration Risks

Inventory and Cost of Sales

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.

Debt Obligation

Net Product Revenue

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

The following table summarizes activity in each of the product revenue allowance and reserve categories for the year ended December 31, 2018:



	Chargebacks			Government Rebates			Total
	(in thousands)
Balance at December 31, 2015:	$	136		$	1,663		$	1,799
Provision recorded during the period	2,081			9,089			11,170
Credit or payments made during the period	(1,749		)	(7,325		)	(9,074		)
Balance at December 31, 2016:	468			3,427			3,895
Provision recorded during the period	2,637			18,097			20,734
Credit or payments made during the period	(2,178		)	(13,563		)	(15,741		)
Balance at December 31, 2017:	927			7,961			8,888
Provision related to current period sales	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

Research and Development

Segment Reporting

Stock-Based Compensation

We recognize the expense of options granted to non-employees based on their fair value at the time of vesting.

Income Taxes

Recently Adopted Accounting Pronouncements and Recently Issued Accounting Pronouncements Not Yet Adopted

Recently Adopted Accounting Pronouncements

Recently Issued Accounting Pronouncements Not Yet Adopted

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

12 Months Ended

Dec. 31, 2018

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, 2018:



	Chargebacks			Government Rebates			Total
	(in thousands)
Balance at December 31, 2015:	$	136		$	1,663		$	1,799
Provision recorded during the period	2,081			9,089			11,170
Credit or payments made during the period	(1,749		)	(7,325		)	(9,074		)
Balance at December 31, 2016:	468			3,427			3,895
Provision recorded during the period	2,637			18,097			20,734
Credit or payments made during the period	(2,178		)	(13,563		)	(15,741		)
Balance at December 31, 2017:	927			7,961			8,888
Provision related to current period sales	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

Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Schedule of Available-for-Sale Securities

Our available-for-sale securities included:



	Fair Value	Estimated Fair Value
	Hierarchy Level	December 31, 2018		December 31, 2017
		(in thousands)
Corporate bonds	Level 2	$	54,469	$	26,116
Commercial paper	Level 2	67,906		32,637
Asset-backed securities	Level 2	10,965		—
Repurchase agreements	Level 2	15,000		—
U.S. treasury securities	Level 1	39,287		14,210
Money market funds	Level 1	4,583		14,979
Total Marketable securities		$	192,210	$	87,942

Classified as:
Cash equivalents		$	27,075	$	14,979
Short-term marketable securities		165,135		57,682
Long-term marketable securities		—		15,281
Total marketable securities		$	192,210	$	87,942

Composition of Certain Balance Sheet Items (Tables)

12 Months Ended

Dec. 31, 2018

Balance Sheet Related Disclosures [Abstract]

Schedule of Composition of Inventory

The composition of inventory was as follows:



	December 31,
	2018			2017
	(in thousands)
Raw materials	$	4,195		$	4,287
Work in progress	5,624			64
Finished goods	6,423			4,025
Total inventory	16,242			8,376
Less strategic inventory classified as non-current	(11,510		)	(3,800		)
Total inventory classified as current	$	4,732		$	4,576

Schedule of Property and Equipment

Property and equipment consisted of the following:



	December 31,
	2018			2017
	(in thousands)
Furniture and equipment	$	361		$	188
Software	884			705
Leasehold improvements	35			14
	1,280			907
Less: accumulated depreciation	(625		)	(389		)
	$	655		$	518

Schedule of Other Accrued Liabilities

Other accrued liabilities consisted of the following:



	December 31,
	2018		2017
	(in thousands)
Government rebates	$	11,132	$	7,961
Accrued compensation	7,879		8,574
Accrued state income taxes	1,542		66
Accrued manufacturing costs	2,032		955
Commercialization costs	261		208
Legal fees	314		276
Professional fees	240		207
Other	386		496
Total other accrued liabilities	$	23,786	$	18,743

Lease Obligations (Tables)

12 Months Ended

Dec. 31, 2018

Leases [Abstract]

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

As of December 31, 2018, future minimum lease payments under non-cancelable operating leases were as follows:



	Lease
	Payments
2019	$	1,563
2020	391
Thereafter	—
Total	$	1,954

Preferred Stock and Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2018

Equity [Abstract]

Summary of Shares of Common Stock Reserved for Future Issuance

Shares of common stock reserved for future issuance as of December 31, 2018 are as follows:



Common stock:	(in thousands)
Exercise of outstanding options	22,826
Shares available for grant under stock option plans	7,726
	30,552

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, 2015	8,070		16,195		$	2.98
Increase in shares authorized for grant	4,386		—
Shares granted	(5,906	)	5,906		$	4.92
Shares exercised	—		(3,068	)	$	2.50
Shares cancelled and forfeited	1,370		(1,370	)	$	3.98
Balance at December 31, 2016	7,920		17,663		$	3.63
Increase in shares authorized for grant	4,508		—
Shares granted	(5,282	)	5,282		$	9.90
Shares exercised	—		(2,007	)	$	3.60
Shares cancelled and forfeited	484		(484	)	$	5.04
Balance at December 31, 2017	7,630		20,454		$	5.22
Increase in shares authorized for grant	4,589
Shares granted	(5,599	)	5,599		$	16.27
Shares exercised	—		(2,121	)	$	4.40
Shares cancelled and forfeited	1,106		(1,106	)	$	11.08
Balance at December 31, 2018	7,726		22,826		$	7.72	6.52	$	146,127

Options exercisable at December 31, 2018			14,117		$	4.97	5.25	$	121,434

Options fully vested and expected to vest at December 31, 2018			22,029		$	7.50	6.44	$	144,813

Summary of Options Outstanding and Exercisable

The following is a summary of options outstanding and options exercisable at December 31, 2018.



Options Outstanding											Options Exercisable
Exercise Prices of Options					Number of Shares	Weighted- Average Remaining Contractual Life	Weighted- Average Exercise Price		Aggregate Intrinsic Value		Number of Shares	Weighted- Average Exercise Price		Aggregate Intrinsic Value
					(in thousands)	(in years)			(in thousands)		(in thousands)			(in thousands)
$	0.96	—	$	4.00	9,187	4.6	$	2.83	$	96,713	8,434	$	2.75	$	89,501
$	4.01	—	$	9.00	6,981	6.6	$	6.58	47,366		4,264	$	6.08	31,056
$	9.01	—	$	17.00	5,784	9.1	$	15.10	2,048		1,269	$	14.27	877
$	17.01	—	$	24.29	874	9.1	$	19.41	—		150	$	19.43	—
					22,826	6.5	$	7.72	$	146,127	14,117	$	4.97	$	121,434

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,
	2018	2017	2016
Weighted-average assumptions for stock options granted:
Risk-free interest rate	2.68%	1.99%	1.31%
Expected term	5.9 years	6.1 years	5.8 years
Expected volatility of stock price	67.9%	68.1%	69.0%
Dividend rate	0%	0%	0%
Weighted-average grant date fair value-based measurement	$10.11	$6.14	$2.98

Summary of Stock-Based Compensation

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



	Year ended December 31,
	2018		2017		2016
	(in thousands)
Stock-based compensation capitalized in inventory	$	87	$	—	$	—
Cost of sales	259		—		—
Research and development	7,012		3,743		1,312
Selling, general and administrative	16,476		9,618		5,746
Total stock-based compensation	$	23,834	$	13,361	$	7,058

- 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.

+ References

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+ Details

Net Income Per Share (Tables)

12 Months Ended

Dec. 31, 2018

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, including the number of weighted-average shares outstanding.



	Year ended December 31,
	2018		2017		2016
	(in thousands)
Numerator:
Net income	$	75,410	$	129,122	$	8,140
Denominator:
Weighted-average shares used to compute basic net income per share	115,343		113,527		110,566
Dilutive effect of employee stock options	11,345		10,988		5,573
Weighted-average shares used to compute diluted net income per share	126,688		124,515		116,139
Net income per share
Basic	$	0.65	$	1.14	$	0.07
Diluted	$	0.60	$	1.04	$	0.07

Schedule of Securities Outstanding that could Potentially Dilute Per Share Data

The following table presents information on securities outstanding as of the end of each period that could potentially dilute the per share data in the future.



	December 31,
	2018	2017	2016
	(in thousands)
Stock options outstanding	22,826	20,454	17,663

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax (Benefit)

The income tax expense (benefit) for the year ended December 31, 2018 and December 31, 2017 consisted of the following:



	Year ended December 31,
	2018			2017
	(in thousands)
U.S. federal taxes:
Current	$	—		$	—
Deferred	14,243			(71,839		)
Total U.S. federal taxes	14,243			(71,839		)
State taxes:
Current	2,676			388
Deferred	(176		)	(4,865		)
Total state taxes	2,500			(4,477		)
Total	$	16,743		$	(76,316	)

Schedule of Significant Components of Deferred Tax Assets

Significant components of our deferred tax assets are as follows:



	December 31,
	2018			2017
Deferred tax assets:	(in thousands)
Federal and state net operating losses	$	23,551		$	41,902
Capitalized research and patent costs	10,260			13,278
Research credits	24,771			22,606
Stock-based compensation costs	9,124			5,596
Other	6,137			5,795
Total deferred tax assets	73,843			89,177
Valuation allowance	(11,184		)	(12,474		)
Net deferred tax assets	$	62,659		$	76,703

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,
	2018			2017			2016
	(in thousands)
U.S. federal taxes at statutory rate	$	19,354		$	17,954		$	2,840
Changes in valuation allowance	—			(119,765		)	(3,679		)
Federal tax rate change impact to change in valuation allowance	—			33,233			—
R&D and other credits	(2,178		)	(1,199		)	(69		)
State income taxes	1,975			(2,955		)	—
Non-deductible Compensation	394			33			2,435
Stock-based compensation	(3,165		)	(3,826		)	(1,660		)
Other	363			209			133
Total	$	16,743		$	(76,316	)	$	—

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,
	2018			2017		2016
Beginning Balance	$	4,139		$	3,527	$	4,342
Increase in tax positions for prior years	—			150		222
Decrease in tax positions for prior years	(135		)	—		(1,189		)
Increase in tax positions for current year	752			462		152
Decrease in tax positions for current year	—			—		—
Ending Balance	$	4,756		$	4,139	$	3,527

Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2018

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
2018
Product revenue, net	$	57,659	$	62,312	$	64,445	$	66,831
Gross profit on product revenue	56,485		61,158		63,137		65,252
Net income	17,459		18,196		17,747		22,008
Basic net income per share	0.15		0.16		0.15		0.19
Diluted net income per share	0.14		0.14		0.14		0.18

2017
Product revenue, net	$	27,599	$	35,559	$	42,763	$	53,280
Gross profit on product revenue	26,953		34,784		41,787		52,123
Net income	4,388		12,647		13,757		98,330
Basic net income per share	0.04		0.11		0.12		0.86
Diluted net income per share	0.04		0.10		0.11		0.77

Basis of Presentation and Summary of Significant Accounting Policies (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 series compound segment supplier	Dec. 31, 2017	Jan. 01, 2019 USD ($)	Aug. 31, 2012 USD ($)
Accounting Policies [Line Items]
Number of series of selective cortisol modulators \| series	3
Number of compounds \| compound	500
Number of manufacturers \| supplier	1
Cumulative payments to be made under financing agreement				$ 45.0
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%
Financing Agreement with Biopharma
Accounting Policies [Line Items]
Payments as a percentage of quarterly sales				20.00%
Minimum \| Scenario, Forecast \| Accounting Standards Update 2016-02
Accounting Policies [Line Items]
Right-of-use asset			$ 1.5
Operating lease liability			1.5
Maximum \| Scenario, Forecast \| Accounting Standards Update 2016-02
Accounting Policies [Line Items]
Right-of-use asset			2.5
Operating lease liability			$ 2.5

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, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts Receivable [Roll Forward}
Balance at beginning of period	$ 8,888	$ 3,895	$ 1,799
Provision recorded during the period		20,734	11,170
Provision related to current period sales	31,315
Provision related to prior period sales	532
Credit or payments made during the period	(29,256)	(15,741)	(9,074)
Balance at end of period	11,479	8,888	3,895
Chargebacks
Allowance for Doubtful Accounts Receivable [Roll Forward}
Balance at beginning of period	927	468	136
Provision recorded during the period		2,637	2,081
Provision related to current period sales	2,687
Provision related to prior period sales	0
Credit or payments made during the period	(3,268)	(2,178)	(1,749)
Balance at end of period	346	927	468
Government Rebates
Allowance for Doubtful Accounts Receivable [Roll Forward}
Balance at beginning of period	7,961	3,427	1,663
Provision recorded during the period		18,097	9,089
Provision related to current period sales	28,628
Provision related to prior period sales	532
Credit or payments made during the period	(25,988)	(13,563)	(7,325)
Balance at end of period	$ 11,133	$ 7,961	$ 3,427

Significant Agreements (Narrative) (Details)		1 Months Ended		12 Months Ended
Significant Agreements (Narrative) (Details)	Jul. 25, 2018 renewal_option	Aug. 31, 2017	Apr. 30, 2014	Dec. 31, 2018 patent
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
Agreement with Alcami Corporation
Debt And Credit Agreements [Line Items]
Initial agreement period			3 years
Automatic extension period			2 years
Agreement termination, written notice period			12 months
Right to terminate agreement if unable to manufacture product, period			4 months
Right to terminate agreement with advanced notice			6 months
Termination notice period for manufacturer			18 months
Treatment Of Triple-Negative Breast Cancer
Debt And Credit Agreements [Line Items]
Number of patents				3
Treatment Of Castration-Resistant Prostate Cancer
Debt And Credit Agreements [Line Items]
Number of patents				2

Fair Value of Financial Instruments (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Marketable securities and money market fund	$ 192.2	$ 87.9
Accumulated unrealized loss on available-for-sale investments	$ 0.1	$ 0.1
Maximum maturity period	2 years
Weighted average maturity period	4 months

Fair Value of Financial Instruments (Schedule of Available-for-Sale Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Short-term marketable securities	$ 165,135	$ 57,682
Long-term marketable securities	0	15,281
Marketable securities	192,200	87,900
Estimated Fair Value
Debt Securities, Available-for-sale [Line Items]
Cash equivalents	27,075	14,979
Short-term marketable securities	165,135	57,682
Long-term marketable securities	0	15,281
Marketable securities	192,210	87,942
Corporate bonds \| Estimated Fair Value \| Level 2
Debt Securities, Available-for-sale [Line Items]
Marketable securities	54,469	26,116
Commercial paper \| Estimated Fair Value \| Level 2
Debt Securities, Available-for-sale [Line Items]
Marketable securities	67,906	32,637
Asset-backed securities \| Estimated Fair Value \| Level 2
Debt Securities, Available-for-sale [Line Items]
Marketable securities	10,965	0
Repurchase agreements \| Estimated Fair Value \| Level 2
Debt Securities, Available-for-sale [Line Items]
Marketable securities	15,000	0
U.S. treasury securities \| Estimated Fair Value \| Level 1
Debt Securities, Available-for-sale [Line Items]
Marketable securities	39,287	14,210
Money market funds \| Estimated Fair Value \| Level 1
Debt Securities, Available-for-sale [Line Items]
Marketable securities	$ 4,583	$ 14,979

Composition of Certain Balance Sheet Items (Composition of Inventory) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Raw materials	$ 4,195	$ 4,287
Work in progress	5,624	64
Finished goods	6,423	4,025
Total inventory	16,242	8,376
Less strategic inventory classified as non-current	(11,510)	(3,800)
Total inventory classified as current	$ 4,732	$ 4,576

Composition of Certain Balance Sheet Items (Property and Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Other Liabilities [Line Items]
Property and equipment	$ 1,280	$ 907
Less: accumulated depreciation	(625)	(389)
Property and equipment net	655	518
Furniture and equipment
Other Liabilities [Line Items]
Property and equipment	361	188
Software
Other Liabilities [Line Items]
Property and equipment	884	705
Leasehold improvements
Other Liabilities [Line Items]
Property and equipment	$ 35	$ 14

Composition of Certain Balance Sheet Items (Other Accrued Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Government rebates	$ 11,132	$ 7,961
Accrued compensation	7,879	8,574
Accrued state income taxes	1,542	66
Accrued manufacturing costs	2,032	955
Commercialization costs	261	208
Legal fees	314	276
Professional fees	240	207
Other	386	496
Total other accrued liabilities	$ 23,786	$ 18,743

Debt Obligation (Narrative) (Details) - USD ($)	12 Months Ended		60 Months Ended
Debt Obligation (Narrative) (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Jul. 31, 2017	Aug. 31, 2012
Contractual Obligation [Line Items]
Cumulative payments to be made under financing agreement				$ 45,000,000
Accretion of interest (income) expense	$ 0	$ 500,000	$ 15,000,000
Issuance costs capitalized				$ 100,000
Unamortized issuance cost	0	$ 0
Financing Agreement with Biopharma
Contractual Obligation [Line Items]
Face amount	$ 30,000,000
Payments as a percentage of quarterly sales				20.00%

Lease Obligations (Narratives) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Leases [Abstract]
Rent expenses	$ 1.3	$ 1.1	$ 0.9

Lease Obligations (Schedule of Future Minimum Lease Payments under Non-Cancelable Operating Leases) (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Leases [Abstract]
2019	$ 1,563
2020	391
Thereafter	0
Total	$ 1,954

Preferred Stock and Stockholders' Equity (Narrative) (Details)		12 Months Ended
	Feb. 08, 2019 shares	Dec. 31, 2018 USD ($) stock_option_plan $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) shares	Aug. 09, 2018 USD ($)	Dec. 31, 2015 shares	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
Increase in shares authorized for grant (in shares)		4,589,000	4,508,000	4,386,000
Number of stock option plans \| stock_option_plan		2
Shares available for future grants (in shares)		7,726,000	7,630,000	7,920,000		8,070,000
Total intrinsic value of options exercised \| $		$ 26,600,000	$ 22,400,000	$ 14,800,000
Fair value of options vested \| $		$ 22,600,000	$ 12,300,000	$ 7,000,000
Number of awards outstanding (in shares)		22,826,000	20,454,000	17,663,000		16,195,000
Aggregate purchase price \| $		$ 23,657,000
Employee and Director Stock Option
Shareholders Equity [Line Items]
Non-cash stock-based compensation expense \| $		23,800,000	$ 13,400,000	$ 7,100,000
Unrecognized compensation expense \| $		$ 56,400,000
Unrecognized compensation expense, weighted-average vesting period		2 years 9 months 18 days
Non-employee
Shareholders Equity [Line Items]
Number of awards outstanding (in shares)		0
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
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%
Shares available for future grants (in shares)							0
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
Subsequent Event \| 2012 Equity Incentive Award Plan
Shareholders Equity [Line Items]
Increase in shares authorized for grant (in shares)	4,600,000
Common Stock \| Stock Repurchase Program
Shareholders Equity [Line Items]
Authorized amount \| $					$ 100,000,000
Shares repurchased (in shares)		1,800,000
Aggregate purchase price \| $		$ 23,700,000
Cost per share (in dollars per share) \| $ / shares		$ 13.09
Remaining authorized amount \| $		$ 76,300,000
Non-employee
Shareholders Equity [Line Items]
Non-cash stock-based compensation expense \| $		$ 0	$ 31,000	$ 56,000

Preferred Stock and Stockholders' Equity (Shares of Common Stock Reserved for Future Issuance) (Details) shares in Thousands	Dec. 31, 2018 shares
Shareholders Equity [Line Items]
Shares of common stock reserved for future issuance (in shares)	30,552
Stock Options Outstanding
Shareholders Equity [Line Items]
Shares of common stock reserved for future issuance (in shares)	22,826
Shares Available For Grant Under Stock Option Plans
Shareholders Equity [Line Items]
Shares of common stock reserved for future issuance (in shares)	7,726

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, 2018	Dec. 31, 2017	Dec. 31, 2016
Shares Available For Future Grant
Beginning balance (in shares)	7,630	7,920	8,070
Increase in shares authorized for grant (in shares)	4,589	4,508	4,386
Shares granted (in shares)	(5,599)	(5,282)	(5,906)
Shares cancelled and forfeited (in shares)	1,106	484	1,370
Ending balance (in shares)	7,726	7,630	7,920
Shares Subject to Options Outstanding
Beginning balance (in shares)	20,454	17,663	16,195
Shares granted (in shares)	5,599	5,282	5,906
Shares exercised (in shares)	(2,121)	(2,007)	(3,068)
Shares cancelled and forfeited (in shares)	(1,106)	(484)	(1,370)
Ending balance (in shares)	22,826	20,454	17,663
Options exercisable (in shares)	14,117
Options fully vested and expected to vest (in shares)	22,029
Outstanding Options, Weighted- Average Exercise Price
Beginning balance (in dollars per share)	$ 5.22	$ 3.63	$ 2.98
Shares granted (in dollars per share)	16.27	9.90	4.92
Shares exercised (in dollars per share)	4.40	3.60	2.50
Shares cancelled and forfeited (in dollars per share)	11.08	5.04	3.98
Ending balance (in dollars per share)	7.72	$ 5.22	$ 3.63
Options exercisable (in dollars per share)	4.97
Options fully vested and expected to vest (in dollars per share)	$ 7.50
Outstanding Options, Weighted Average Remaining Contractual Life
Weighted average remaining contractual life	6 years 6 months 7 days
Weighted average remaining contractual life, Options exercisable	5 years 3 months
Weighted average remaining contractual life, Options fully vested and expected to vest	6 years 5 months 9 days
Outstanding Options, Aggregate Intrinsic Value
Aggregate Intrinsic Value	$ 146,127
Options exercisable	121,434
Options fully vested and expected to vest	$ 144,813

Preferred Stock and Stockholders' Equity (Summary of Options Outstanding and Exercisable) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number of Shares (in shares)	22,826	20,454	17,663	16,195
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	6 years 6 months 7 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 7.72	$ 5.22	$ 3.63	$ 2.98
Options Outstanding, Aggregate Intrinsic Value	$ 146,127
Options Exercisable, Number of Shares (in shares)	14,117
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 4.97
Options Exercisable, Aggregate Intrinsic Value	$ 121,434
$0.96 - $ 4.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Of Options, minimum (in dollars per share)	$ 0.96
Exercise Price Of Options, maximum (in dollars per share)	$ 4.00
Options Outstanding, Number of Shares (in shares)	9,187
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	4 years 7 months 6 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 2.83
Options Outstanding, Aggregate Intrinsic Value	$ 96,713
Options Exercisable, Number of Shares (in shares)	8,434
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 2.75
Options Exercisable, Aggregate Intrinsic Value	$ 89,501
$4.01 - $ 9.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Of Options, minimum (in dollars per share)	$ 4.01
Exercise Price Of Options, maximum (in dollars per share)	$ 9.00
Options Outstanding, Number of Shares (in shares)	6,981
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	6 years 7 months 6 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 6.58
Options Outstanding, Aggregate Intrinsic Value	$ 47,366
Options Exercisable, Number of Shares (in shares)	4,264
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 6.08
Options Exercisable, Aggregate Intrinsic Value	$ 31,056
$9.01 - $ 17.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Of Options, minimum (in dollars per share)	$ 9.01
Exercise Price Of Options, maximum (in dollars per share)	$ 17.00
Options Outstanding, Number of Shares (in shares)	5,784
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	9 years 1 month 6 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 15.10
Options Outstanding, Aggregate Intrinsic Value	$ 2,048
Options Exercisable, Number of Shares (in shares)	1,269
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 14.27
Options Exercisable, Aggregate Intrinsic Value	$ 877
$17.01 - $ 24.29
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Of Options, minimum (in dollars per share)	$ 17.01
Exercise Price Of Options, maximum (in dollars per share)	$ 24.29
Options Outstanding, Number of Shares (in shares)	874
Options Outstanding, Weighted Average Remaining Contractual Life (in years)	9 years 1 month 6 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 19.41
Options Outstanding, Aggregate Intrinsic Value	$ 0
Options Exercisable, Number of Shares (in shares)	150
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 19.43
Options Exercisable, Aggregate Intrinsic Value	$ 0

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, 2018	Dec. 31, 2017	Dec. 31, 2016
Weighted-average assumptions for stock options granted:
Risk-free interest rate	2.68%	1.99%	1.31%
Expected term	5 years 10 months 24 days	6 years 1 month 6 days	5 years 9 months 18 days
Expected volatility of stock price	67.90%	68.10%	69.00%
Dividend rate	0.00%	0.00%	0.00%
Weighted-average grant date fair value-based measurement (in dollars per share)	$ 10.11	$ 6.14	$ 2.98

Preferred Stock and Stockholders' Equity (Summary of Stock-Based Compensation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation capitalized in inventory	$ 87	$ 0	$ 0
Total stock-based compensation	23,834	13,361	7,058
Cost of sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	259	0	0
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	7,012	3,743	1,312
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 16,476	$ 9,618	$ 5,746

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, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator:
Net income	$ 22,008	$ 17,747	$ 18,196	$ 17,459	$ 98,330	$ 13,757	$ 12,647	$ 4,388	$ 75,410	$ 129,122	$ 8,140
Denominator:
Weighted-average shares used to compute basic net income per share (in shares)									115,343	113,527	110,566
Dilutive effect of employee stock options (in shares)									11,345	10,988	5,573
Weighted-average shares used to compute diluted net income per share (in shares)									126,688	124,515	116,139
Net income per share
Basic (in dollars per share)	$ 0.19	$ 0.15	$ 0.16	$ 0.15	$ 0.86	$ 0.12	$ 0.11	$ 0.04	$ 0.65	$ 1.14	$ 0.07
Diluted (in dollars per share)	$ 0.18	$ 0.14	$ 0.14	$ 0.14	$ 0.77	$ 0.11	$ 0.10	$ 0.04	$ 0.60	$ 1.04	$ 0.07

- Definition

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

+ References

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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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+ Details

- Definition

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

+ References + Details

Net Income Per Share (Details) - shares shares in Millions	12 Months Ended
Net Income Per Share (Details) - shares shares in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
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)	5.0	1.1	4.4

Net Income Per Share (Securities Outstanding that could Potentially Dilute Per Share Data) (Details) - shares shares in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Securities outstanding that could potentially dilute per share data	22,826	20,454	17,663

Income Taxes (Components of Income Tax (Benefit)) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
U.S. federal taxes:
Current	$ 0	$ 0
Deferred	14,243,000	(71,839,000)
Total U.S. federal taxes	14,243,000	(71,839,000)
State taxes:
Current	2,676,000	388,000
Deferred	(176,000)	(4,865,000)
Total state taxes	2,500,000	(4,477,000)
Total	$ 16,743,000	$ (76,316,000)	$ 0

Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
Income Taxes (Narrative) (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Income tax expense (benefit)	$ 16,743,000	$ (76,316,000)	$ 0
Tax cuts and jobs act, change in tax rate, income tax expense (benefit)		33,200,000
Decrease in valuation allowance	1,300,000	116,900,000	4,300,000
Unrecognized tax benefits	4,756,000	4,139,000	3,527,000	$ 4,342,000
Unrecognized tax benefits, accrued interest	0	0	0
Unrecognized tax benefits, accrued penalties	0	$ 0	$ 0
Federal
Income Taxes [Line Items]
Net operating loss carryforwards	76,800,000
Research and development tax credits	$ 21,000,000
Minimum \| Federal
Income Taxes [Line Items]
Net operating loss carryforwards, expiration year	2031
Research and development tax credit, expiration year	2023
Maximum \| Federal
Income Taxes [Line Items]
Net operating loss carryforwards, expiration year	2036
Research and development tax credit, expiration year	2038
California State
Income Taxes [Line Items]
Net operating loss carryforwards	$ 69,100,000
Research and development tax credits	$ 4,600,000
California State \| Minimum
Income Taxes [Line Items]
Net operating loss carryforwards, expiration year	2019
California State \| Maximum
Income Taxes [Line Items]
Net operating loss carryforwards, expiration year	2036
Other States
Income Taxes [Line Items]
Net operating loss carryforwards	$ 9,400,000
Other States \| Minimum
Income Taxes [Line Items]
Net operating loss carryforwards, expiration year	2023
Other States \| Maximum
Income Taxes [Line Items]
Net operating loss carryforwards, expiration year	2036

Income Taxes (Significant Components of Deferred Tax Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Federal and state net operating losses	$ 23,551	$ 41,902
Capitalized research and patent costs	10,260	13,278
Research credits	24,771	22,606
Stock-based compensation costs	9,124	5,596
Other	6,137	5,795
Total deferred tax assets	73,843	89,177
Valuation allowance	(11,184)	(12,474)
Net deferred tax assets	$ 62,659	$ 76,703

Income Taxes (Reconciliation of Statutory Federal Income Tax Rate to Effective Rate) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
U.S. federal taxes at statutory rate	$ 19,354,000	$ 17,954,000	$ 2,840,000
Changes in valuation allowance	0	(119,765,000)	(3,679,000)
Federal tax rate change impact to change in valuation allowance	0	33,233,000	0
R&D and other credits	(2,178,000)	(1,199,000)	(69,000)
State income taxes	1,975,000	(2,955,000)	0
Non-deductible Compensation	394,000	33,000	2,435,000
Stock-based compensation	(3,165,000)	(3,826,000)	(1,660,000)
Other	363,000	209,000	133,000
Total	$ 16,743,000	$ (76,316,000)	$ 0

Income Taxes (Changes in Balance of Gross Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning Balance	$ 4,139	$ 3,527	$ 4,342
Increase in tax positions for prior years	0	150	222
Decrease in tax positions for prior years	(135)	0	(1,189)
Increase in tax positions for current year	752	462	152
Decrease in tax positions for current year	0	0	0
Ending Balance	$ 4,756	$ 4,139	$ 3,527

Commitments and contingencies (Narratives) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jan. 31, 2018	Dec. 31, 2018
Commitment And Contingencies [Line Items]
Losses for contingent liability		$ 0
Provision for a loss contingency		0
Dohmen Life Science Services
Commitment And Contingencies [Line Items]
Amount received under settlement agreement	$ 12,900,000
Dohmen Life Science Services \| Other Receivable
Commitment And Contingencies [Line Items]
Net receivables outstanding		$ 12,900,000

Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Product revenue, net	$ 66,831	$ 64,445	$ 62,312	$ 57,659	$ 53,280	$ 42,763	$ 35,559	$ 27,599	$ 251,247	$ 159,201	$ 81,321
Gross profit on product revenue	65,252	63,137	61,158	56,485	52,123	41,787	34,784	26,953
Net income	$ 22,008	$ 17,747	$ 18,196	$ 17,459	$ 98,330	$ 13,757	$ 12,647	$ 4,388	$ 75,410	$ 129,122	$ 8,140
Basic net income per share (in dollars per share)	$ 0.19	$ 0.15	$ 0.16	$ 0.15	$ 0.86	$ 0.12	$ 0.11	$ 0.04	$ 0.65	$ 1.14	$ 0.07
Diluted net income per share (in dollars per share)	$ 0.18	$ 0.14	$ 0.14	$ 0.14	$ 0.77	$ 0.11	$ 0.10	$ 0.04	$ 0.60	$ 1.04	$ 0.07

- Definition

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

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

+ References + Details