Intercept Pharmaceuticals (ICPT) 10-Q 10 May 18 2018 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information	3 Months Ended
	Mar. 31, 2018shares
Document and Entity Information [Abstract]
Entity Registrant Name	INTERCEPT PHARMACEUTICALS, INC.
Entity Central Index Key	1,270,073
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Trading Symbol	icpt
Entity Common Stock, Shares Outstanding	25,331,808
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2018
Document Fiscal Period Focus	Q1
Document Fiscal Year Focus	2,018

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 48,871	$ 70,013
Investment securities, available-for-sale	277,221	344,904
Accounts receivable, net	16,944	16,501
Prepaid expenses and other current assets	20,809	16,889
Total current assets	363,845	448,307
Fixed assets, net	14,074	16,184
Inventory, net	7,938	3,480
Security deposits	7,961	16,376
Total assets	393,818	484,347
Current liabilities:
Accounts payable, accrued expenses and other liabilities	74,087	94,777
Short-term interest payable	3,737	7,475
Short-term portion of deferred revenue	1,622	1,782
Total current liabilities	79,446	104,034
Long-term liabilities:
Long-term debt	359,449	355,677
Long-term other liabilities	5,171	5,578
Long-term portion of deferred revenue	2,027	2,672
Total liabilities	446,093	467,961
Stockholders' equity:
Common stock par value $0.001 per share; 45,000,000 shares authorized; 25,331,808 and 25,172,678 shares issued and outstanding as of March 31, 2018 and December 31, 2017, respectively	25	25
Additional paid-in capital	1,499,476	1,486,690
Accumulated other comprehensive loss, net	(643)	(786)
Accumulated deficit	(1,551,133)	(1,469,543)
Total stockholders' equity	(52,275)	16,386
Total liabilities and stockholders' equity	$ 393,818	$ 484,347

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Common stock, authorized	45,000,000	45,000,000
Common stock, shares, issued	25,331,808	25,172,678
Common stock, shares, outstanding	25,331,808	25,172,678
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
Product revenue, net	$ 35,158	$ 20,603
Licensing revenue	805	445
Total revenue	35,963	21,048
Operating expenses:
Cost of sales	280	97
Selling, general and administrative	62,467	61,082
Research and development	48,672	43,832
Total operating expenses	111,419	105,011
Operating loss	(75,456)	(83,963)
Other income (expense):
Interest expense	(7,509)	(7,207)
Other income, net	1,375	1,240
Total other income (expense)	(6,134)	(5,967)
Net loss	$ (81,590)	$ (89,930)
Net Loss Per Share [Abstract]
Net loss per share, basic and diluted (in dollars per share)	$ (3.22)	$ (3.61)
Weighted average shares outstanding, basic and diluted	25,309	24,931

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Comprehensive Loss:
Net loss	$ (81,590)	$ (89,930)
Unrealized holding gains (losses) arising during the period	374	414
Net unrealized gains (losses) on marketable investment securities	374	414
Foreign currency translation adjustments	517	205
Comprehensive loss	$ (80,699)	$ (89,311)

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net loss	$ (81,590)	$ (89,930)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	12,305	14,061
Amortization of investment premium	502	1,022
Amortization of deferred financing costs	373	343
Depreciation	1,290	802
Loss on disposal of fixed assets	901
Accretion of debt discount	3,399	3,126
Changes in operating assets:
Prepaid expenses and other current assets	(3,920)	(6,994)
Accounts receivable	(443)	(1,499)
Inventory	(4,458)	163
Security deposits	8,415	1,414
Changes in operating liabilities:
Accounts payable, accrued expenses, and other current liabilities	(20,690)	(2,628)
Long-term other liabilities	(407)	6,268
Interest payable	(3,738)	(3,529)
Deferred revenue	(805)	(119)
Net cash used in operating activities	(88,866)	(77,500)
Cash flows from investing activities:
Purchases of investment securities	(28,466)	(21,246)
Sales of investment securities	95,273	125,285
Purchases of equipment, leasehold improvements, and furniture and fixtures	(89)	(4,025)
Net cash provided by (used in) investing activities	66,718	100,014
Cash flows from financing activities:
Proceeds from exercise of options, net	481	556
Net cash provided by financing activities	481	556
Effect of exchange rate changes	525	205
Net increase in cash and cash equivalents	(21,142)	23,275
Cash and cash equivalents - beginning of period	70,013	43,675
Cash and cash equivalents - end of period	$ 48,871	$ 66,950

Overview of Business

Overview of Business	3 Months Ended
	Mar. 31, 2018
Overview of Business [Abstract]
Overview of Business	   1. Overview of Business  Intercept Pharmaceuticals, Inc. (“Intercept” or the “Company”) is a biopharmaceutical company focused on the development and commercialization of novel therapeutics to treat progressive non-viral liver diseases, including primary biliary cholangitis (“PBC”), nonalcoholic steatohepatitis (“NASH”), primary sclerosing cholangitis (“PSC”) and biliary atresia. The Company currently has one marketed product, Ocaliva (obeticholic acid or “OCA”). Founded in 2002 in New York, Intercept has operations in the United States, Europe and Canada.

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2018
Overview of Business [Abstract]
Basis of Presentation	2. Basis of Presentation  The Company’s financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). All intercompany accounts and transactions have been eliminated. Certain information that is normally required by U.S. GAAP has been condensed or omitted in accordance with rules and regulations of the Securities and Exchange Commission (“SEC”). Operating results for the three months ended March 31, 2018 are not necessarily indicative of the results that may be expected for any future period or for the year ending December 31, 201 8 . In the opinion of management, these unaudited condensed consolidated financial statements include all normal and recurring adjustments considered necessary for a fair presentation of these interim unaudited condensed consolidated financial statements.  These unaudited condensed consolidated financial statements should be read in conjunction with the Company's audited consolidated financial statements and the notes thereto for the year ended December 31, 2017 , included in the Company’s 2017 Annual Report on Form 10-K filed with the SEC.  Use of Estimates  The preparation of these unaudited consolidated condensed financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, expenses, revenues and related disclosures. Significant estimates include: clinical trial accruals, revenues and stock-based compensation expense. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions .

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2018
Summary of Significant Accounting Policies [Abstract]
Summary of Significant Accounting Policies	3. Summary of Significant Accounting Policies The Company’s significant accounting policies are described in Note 3 of Notes to Consolidated Financial Statements included in its Annual Report on Form 10-K for the year ended December 31, 2017 .  Revenue Recognition  Product Re venue, Net  The Com pany commenced its commercial launch of Ocaliva for the treatment of PBC in the United States in June 2016. In December 2016, the European Commission granted conditional approval for Ocaliva for the treatment of PBC and the Company commenced its European commercial launch in January 2017. In May 2017, Health Canada granted a conditional approval for Ocaliva for the treatment of PBC and the Company commenced its commercial launch in July 2017. The Company sells Ocaliva to a limited number of specialty pharmacies which dispense the product directly to patients. The specialty pharmacies are referred to as the Company’s customers. The Company provides the right of return to its customers for unopened product for a limited time before and after its expiration date. Prior to July 2017, given the Company’s limited sales history for Ocaliva and the inherent uncertainties in estimating product returns, the Company determined that the shipments of Ocaliva made to its customers did not meet the criteria for revenue recognition at the time of shipment. Accordingly, the Company recognized revenue when the product was sold through by its customers, provided all other revenue recognition criteria were met. The Company invoiced its customers upon shipment of Ocaliva to them and recorded accounts receivable, with a corresponding liability for deferred revenue equal to the gross invoice price. The Company then recognized revenue when Ocaliva was sold through as specialty pharmacies dispensed product directly to the patients (sell-through basis).  The Company re-evaluated its revenue recognition policy in the third quarter of 2017, which included the accumulation and review of customer related transactions since the Company’s commercial launch in the second quarter of 2016. The Company concluded it had accumulated sufficient data to reasonably estimate product returns and, therefore, began to recognize revenue at the time of shipment to its customers (sell-in basis). During the third quarter of 2017, the Company recorded an adjustment related to this change in estimate to recognize previously deferred revenue. The net effect was an increase in net sales of Ocaliva of $4.1 million for the nine months ended September 30, 2017. The Company also established a new reserve of $0.7 million during the third quarter of 2017 related to future returns from its customers under its various contracts.  Effective January 1, 2018, the Company recognizes revenue under Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with C ustomers (“ASC 606”) . The core principle of the new revenue standard is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. The following five steps are applied to achieve that core principle: " Step 1: Identify the contract with the customer " Step 2: Identify the performance obligations in the contract " Step 3: Determine the transaction price " Step 4: Allocate the transaction price to the performance obligations in the contract " Step 5: Recognize revenue when the company satisfies a performance obligation  In order to identify the performance obligations in a contract with a customer, a company must assess the promised goods or services in the contract and identify each promised good or service that is distinct. A performance obligation meets ASC 606’s definition of a “distinct” good or service (or bundle of goods or services) if both of the following criteria are met:  " The customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (i.e., the good or service is capable of being distinct). • The entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (i.e., the promise to transfer the good or service is distinct within the context of the contract).  If a good or service is not distinct, the good or service is combined with other promised goods or services until a bundle of goods or services is identified that is distinct.  The transaction price is the amount of consideration to which an entity expects to be entitled in exchange for transferring promised goods or services to a customer, excluding amounts collected on behalf of third parties (for example, some sales taxes). The consideration promised in a contract with a customer may include fixed amounts, variable amounts, or both. Variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved.  The transaction price is allocated to each performance obligation on a relative standalone selling price basis. The transaction price allocated to each performance obligation is recognized when that performance obligation is satisfied, at a point in time or over time as appropriate. Under ASC 606, the Company has written contracts with each of its customers that have a single performance obligation – to deliver products upon receipt of a customer order – and these obligations are satisfied when delivery occurs and the customer receives Ocaliva. The Company evaluates the creditworthiness of each of its customers to determine whether collection is reasonably assured. The Company estimates variable revenue by calculating gross product revenues based on the wholesale acquisition cost that the Company charges its customers for Ocaliva, and then estimating its net product revenues by deducting (i) trade allowances, such as invoice discounts for prompt payment and customer fees, (ii) estimated government rebates and discounts related to Medicare, Medicaid and other government programs, and (iii) estimated costs of incentives offered to certain indirect customers including patients. Trade Allowances The Company provides invoice discounts on Ocaliva sales to certain of its customers for prompt payment and records these discounts as a reduction to gross product revenues. These discounts are based on contractual terms. Rebates and Discounts The Company contracts with Centers for Medicare & Medicaid Services (“CMS”) and other government agencies to make Ocaliva available to eligible patients. As a result, the Company estimates any rebates and discounts and deducts these estimated amounts from its gross product revenues at the time the revenues are recognized. The Company’s estimates of rebates and discounts are based on the government mandated discounts, which are statutorily-defined and applicable to these government funded programs. These estimates are recorded in accrued liabilities on the consolidated balance sheet. Other Incentives Other incentives that the Company offers to indirect customers include co-pay assistance cards provided by the Company for PBC patients whom reside in states that permit co-pay assistance programs. The Company’s co-pay assistance program is intended to reduce each participating patient’s portion of the financial responsibility for Ocaliva purchase price to a specified dollar amount. The Company estimates each period the amount of co-pay assistance provided to eligible patients based on the terms of the program when product is dispensed by the specialty pharmacies to the patients. These estimates are based on redemption information provided by third-party claims processing organizations and are recorded in accrued liabilities on the consolidated balance sheet. Because the Company changed its revenue recognition polices to the sell-in basis during the third quarter of 2017, the adoption of ASU 2014-09 (as defined below) , via a modified retrospective approach applied to all contracts not completed at January 1, 2018, did not result in an adjustment to amounts previously recognized as revenue under ASC Topic 605 , Revenue Recognition (“ASC 605”) , and there were no other significant changes impacting the timing or measurement of the Company’s revenue or the Company’s business processes and controls.  Licensing Revenue Under ASC 606, the Company accounts for the development, regulatory and sales milestones within an arrangement as variable consideration that is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. Because the achievement of the milestones triggering these payments is highly susceptible to factors outside the entity’s influence, and the uncertainty about the amount of consideration for some of the milestones is not expected to be resolved for a long period of time, the Company does not expect to record the associated revenue until achievement of each milestone is imminent or has already occurred. Adoption of ASC 606 did not result in any adjustment to licensing revenue previously recognized under ASC 605. Recent Acco unting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, “Revenue from Contracts with Customers (Topic 606)” ( “ ASU 2014-09 ” ), and subsequently issued mo difications or clarifications in ASU No. 2015-14, “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date,” ASU 2016-08, “Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net),” ASU No. 2016-10, “Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing,” and ASU No. 2016-12, “Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients.” The revenue recognition principle in ASU 2014-09 and the related guidance is that an entity should recognize revenue to depict the transfer of goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASU 2014-09 prescribes a five-step process for evaluating contracts and determining revenue recognition. In addition, new and enhanced disclosures are required. Companies may adopt the new standard either using the full retrospective approach, a modified retrospective approach with practical expedients, or a cumulative effect upon adoption approach. The Company adopted the new standard on January 1, 2018, using the modified retrospective approach, applied only to contracts that were not completed as of January 1, 2018. In January 2016, FASB issued ASU 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities (“ASU 2016-01”). ASU 2016-01 requires equity investments to be measured at fair value with changes in fair value recognized in net income; simplifies the impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment; eliminates the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; requires an entity to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; requires separate presentation of financial assets and financial liabilities by measurement category and form of financial assets on the balance sheet or the accompanying notes to the financial statements and clarifies that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity’s other deferred tax assets. ASU 2016-01 is effective for financial statements issued for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. The Company adopted ASU 2016-01 on January 1, 2018 and its adoption did not have a material impact on the Company’s consolidated financial statements and related disclosures. In February 2016, the FASB issued ASU 2016-02, Leases (“ASU 2016-02”) which supersedes Topic 840, Leases. ASU 2016-02 requires lessees to recognize a right-of-use asset and a lease liability on their balance sheets for all the leases with terms greater than twelve months. Based on certain criteria, leases will be classified as either financing or operating, with classification affecting the pattern of expense recognition in the income statement. For leases with a term of twelve months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. If a lessee makes this election, it should recognize lease expense for such leases generally on a straight-line basis over the lease term. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, and interim periods within those years, with early adoption permitted. In transition, lessees and lessors are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. The modified retrospective approach includes a number of optional practical expedients primarily focused on leases that commenced before the effective date of Topic 842, including continuing to account for leases that commence before the effective date in accordance with previous guidance, unless the lease is modified. The Company is evaluating the impact of the adoption of the standard on its consolidated financial statements and related disclosures. In May 2017, the FASB issued ASU 2017-09, Compensation-Stock Compensation (Topic 718): Scope of Modification Accounting (“ASU 2017-09”), which clarifies when to account for a change to the terms or conditions of a stock -based payment award as a modification. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) changes as a result of the change in terms or conditions. It is effective prospectively for the annual period ending December 31, 2018 and interim periods within that annual period. Early adoption is permitted. The Company adopted ASU 2017-09 on January 1, 2018 and its adoption did not have a material impact on the consolidated financial statements and related disclosures. In July 2017, the FASB issued ASU 2017-11, Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480) and Derivatives and Hedging (Topic 815): I. Accounting for Certain Financial Instruments with Down Round Features; II. Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception ( “ ASU 2017-11 ” ). Part I of this update addresses the complexity of accounting for certain financial instruments with down round features. Down round features are features of certain equity-linked instruments (or embedded features) that result in the strike price being reduced on the basis of the pricing of future equity offerings. Current accounting guidance creates cost and complexity for entities that issue financial instruments (such as warrants and convertible instruments) with down round features that require fair value measurement of the entire instrument or conversion option. Part II of this update addresses the difficulty of navigating Topic 480, Distinguishing Liabilities from Equity, because of the existence of extensive pending content in the FASB Accounting Standards Codification. This pending content is the result of the indefinite deferral of accounting requirements about mandatorily redeemable financial instruments of certain nonpublic entities and certain mandatorily redeemable noncontrolling interests. The amendments in Part II of this update do not have an accounting effect. This ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018. The Company is currently assessing the potential impact of adopting ASU 2017-11 on its financial statements and related disclosures, but does not expect it to have a significant impact.

Significant Agreements

Significant Agreements	3 Months Ended
	Mar. 31, 2018
Significant Agreements [Abstract]
Significant Agreements	   4. Significant Agreements Sumitomo Dainippon Pharma Co ., Ltd . In March 2011, the Company entered into an exclusive license agreement (the “Original License Agreement”) with Sumitomo Dainippon Pharma Co., Ltd. (“ Sumitomo Dainippon”), pursuant to which the Company granted to Sumitomo Dainippon an exclusive license to research, develop and commercialize OCA for the treatment of PBC and NASH in Japan and China (excluding Taiwan) and an option to research, develop and commercialize OCA in certain countries outside of such territories (the “Country Option”) . The Company received an upfront payment from Sumitomo Dainippon of $15.0 million under the terms of the Original License Agreement. In May 2014, Sumitomo Dainippon exercised the Country Option in part to add Korea as part of its licensed territories and paid the Company a $1.0 million upfront fee in connection therewith. In February 2018, the Company and Sumitomo Dainippon entered into Amendment No. 3 (the “Sumitomo Amendment”) to the Original License Agreement (as amended, the “License Agreement”). Pursuant to the Sumitomo Amendment, (i) Sumitomo Dainippon agreed to return the rights to develop and commercialize OCA in Japan and Korea and waived its rights to the Country Option, (ii) the Company agreed to forego any further milestone or royalty payments relating to the development and commercialization of OCA in Japan and Korea and (iii) certain milestone payment obligations with respect to the development and commercialization of OCA were adjusted. In addition, the Company and Sumitomo Dainippon agreed that if certain clinical development milestones in China are not met by December 31, 2020, Sumitomo Dainippon may choose either to make a milestone payment to the Company or terminate the License Agreement. As of March 31, 2018, the Company had achieved $6.0 million of development milestones under the License Agreement. The Comp any may be eligible to receive additional milestone payments under the License Agreement in an aggregate amount of up to approximately $23.0 million based on the occurrence of certain clinical trial and regulatory-related events and tiered royalty payments up to the mid-twenties in percentage terms based on net sales of OCA products in China (excluding Taiwan). Sumitomo Dainippon is responsible for the costs of developing and commercializing OCA in its territories. The Company has concluded that Sumitomo Dainippon does not represent a customer of the Company, and therefore the license agreement is outside of the scope of ASC 606. The Company has and continues to account for this agreement under the legacy accounting guidance. Under ASC 605, Revenue Recognition, the Company evaluated the license agreement with Sumitomo Dainippon and determined that it is a revenue arrangement with multiple deliverables, or performance ob ligations. The Company’s substantive performance obligations under this license include an exclusive license to its technology, technical and scientific support to the development plan and participation on a joint steering committee. The Company determined that these performance obligations represent a single unit of accounting, since, initially, the license does not have stand-alone value to Sumitomo Dainippon without the Company’s technical expertise and steering committee participation during the development of OCA. Th e development period is currently estimated as continuing through June 2020 and, as such, the $15.0 million upfront payment is being recognized ratably over this period. During the three months ended March 31, 2018 and 2017 , th e Company recorded licensing revenue of approximately $0.8 million and $0.4 million, respectively, under this agreement. Included in licensing revenue for the three months ended March 31, 2018 is $0.4 million related to the accelerated recognition, as a result of the Sumitomo Amendment, of the remaining portion of deferred revenue associated with the $1.0 million upfront payment that the Company received under the Original License Agreement in connection with Sumitomo Dainippon’s exercise of the Country Option with respect to Korea. The Company recognizes milestone payments when the associated milestones are achieved. As of March 31, 2018, and December 31, 2017, the Company had recorded deferred revenues of $3.6 million and $4.5 million, respectively , under this agreemen t.

Cash, Cash Equivalents and Inve

Cash, Cash Equivalents and Investments	3 Months Ended
	Mar. 31, 2018
Cash, Cash Equivalents, and Investments [Abstract]
Cash, Cash Equivalents, and Investments	   5. Cash, Cash Equivalents and Investments  The following table summarizes the Company’s cash, cash equivalents and investments as of March 31, 2018 and December 31, 2017 :    As of March 31, 2018  Gross Gross  Unrealized Unrealized  Amortized Cost Gains Losses Fair Value   (In thousands)  Cash and cash equivalents:  Cash and money market funds $ 48,871 $ - $ - $ 48,871  Investment securities:  Commercial paper 8,909 - (31) 8,878  Corporate debt securities 263,476 - (1,098) 262,378  U.S. government and agency securities 5,995 - (30) 5,965  Total investments 278,380 - (1,159) 277,221  Total cash, cash equivalents and investments $ 327,251 $ - $ (1,159) $ 326,092     As of December 31, 2017  Gross Gross  Unrealized Unrealized  Amortized Cost Gains Losses Fair Value   (In thousands)  Cash and cash equivalents:  Cash and money market funds $ 70,013 $ - $ - $ 70,013  Investment securities:  Commercial paper 2,986 - (3) 2,983  Corporate debt securities 333,958 - (752) 333,206  U.S. government and agency securities 8,743 - (28) 8,715  Total investments 345,687 - (783) 344,904  Total cash, cash equivalents and investments $ 415,700 $ - $ (783) $ 414,917 As of March 31, 2018 , the Company held a total of nineteen positions that were in a continuous unrealized loss position for more than twelve months. The Company has determined that the unrealized losses are deemed to be temporary impairments as of March 31, 2018 . The Company believes that the unrealized losses generally are caused by increases in the risk premiums required by market participants rather than an adverse change in cash flows or a fundamental weakness in the credit quality of the issuer or underlying assets. Because the Company has the ability and intent to hold these investments until a recovery of fair value, which may be maturity, it does not consider the investments to be other-than-temporarily impaired at March 31, 2018 .

Fixed Assets, Net

Fixed Assets, Net	3 Months Ended
	Mar. 31, 2018
Fixed Assets, Net [Abstract]
Fixed Assets, Net	  6. Fixed Assets, Net  Fixed assets are stated at cost and depreciated or amortized using the straight-line method based on useful lives as follows:      Useful lives  (Years) March 31, 2018 December 31, 2017  (In thousands)  Office equipment and software 3 $ 4,049 $ 5,048  Leasehold improvements Over life of lease 14,722 14,665  Furniture and fixtures 7 4,334 5,257  Subtotal 23,105 24,970  Less: accumulated depreciation (9,031) (8,786)  Fixed assets, net $ 14,074 $ 16,184 

Inventory, Net

Inventory, Net	3 Months Ended
	Mar. 31, 2018
Inventory, Net [Abstract]
Inventory, Net	  7. Inventory, Net   Inventories are stated at the lower of cost or market. Inventories consist ed of the following:    March 31, 2018 December 31, 2017  (In thousands)  Work-in-process $ 7,713 $ 3,249  Finished goods 225 231  Inventory, net $ 7,938 $ 3,480 

Accounts Payable, Accrued Expen

Accounts Payable, Accrued Expenses and Other Liabilities	3 Months Ended
	Mar. 31, 2018
Accounts Payable, Accrued Expenses and Other Liabilities [Abstract]
Accounts Payable, Accrued Expenses and Other Liabilities	  8. Accounts Payable, Accrued Expenses and Other Liabilities  Accounts payable, accrued expenses and other liabilities consisted of the following:    March 31, 2018 December 31, 2017  (In thousands)  Accounts payable $ 13,545 $ 6,965  Accrued contracted services 37,984 51,154  Accrued employee compensation 11,600 27,118  Other liabilities 10,958 9,540  Accounts payable, accrued expenses and other liabilities $ 74,087 $ 94,777 

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
Fair Value Measurements [Abstract]
Fair Value Measurements	7   9. Fair Value Measurements The carrying amounts of the Company’s receivables and payables approximate their fair value due to their short maturities.  Accounting principles provide guidance for using fair value to measure assets and liabilities. The guidance includes a three-level hierarchy of valuation techniques used to measure fair value, defined as follows:  · Unadjusted Quoted Prices — The fair value of an asset or liability is based on unadjusted quoted prices in active markets for identical assets or liabilities (Level 1). · Pricing Models with Significant Observable Inputs — The fair value of an asset or liability is based on information derived from either an active market quoted price, which may require further adjustment based on the attributes of the financial asset or liability being measured, or an inactive market transaction (Level 2). · Pricing Models with Significant Unobservable Inputs — The fair value of an asset or liability is primarily based on internally derived assumptions surrounding the timing and amount of expected cash flows for the financial instrument. Therefore, these assumptions are unobservable in either an active or inactive market (Level 3).   The Company considers an active market as one in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis. Conversely, the Company views an inactive market as one in which there are few transactions for the asset or liability, the prices are not current, or price quotations vary substantially either over time or among market makers. Where appropriate, non-performance risk, or that of a counterparty, is considered in determining the fair values of liabilities and assets, respectively.  The Company’s cash deposits and money market funds are classified within Level 1 of the fair value hierarchy because they are valued using bank balances or quoted market prices. Investments are classified as Level 2 instruments based on market pricing and other observable inputs.  Financial assets carried at fair value are classified in the tables below in one of the three categories described above:         Fair Value Measurements Using  Total Level 1 Level 2 Level 3  (In thousands)  March 31, 2018  Assets:  Money market funds (included in cash and cash equivalents) $ 10,239 $ 10,239 $ - $ -  Available for sale securities:  Commercial paper 8,878 - 8,878 -  Corporate debt securities 262,378 - 262,378 -  U.S. government and agency securities 5,965 - 5,965 -  Total financial assets: $ 287,460 $ 10,239 $ 277,221 $ -   December 31, 2017  Assets:  Money market funds (included in cash and cash equivalents) $ 13,361 $ 13,361 $ - $ -  Available for sale securities:  Commercial paper 2,983 - 2,983 -  Corporate debt securities 333,206 - 333,206 -  U.S. government and agency securities 8,715 - 8,715 -  Total financial assets $ 358,265 $ 13,361 $ 344,904 $ - The estimated fair value of marketable debt securities (commercial paper, corporate debt securities and U.S. government and agency securities), by contractual maturity, are as follows:       Fair Value as of  March 31, 2018 December 31, 2017  (In thousands)  Due in one year or less $ 222,895 $ 282,159  Due after 1 year through 2 years 54,326 62,745  Total investments in debt securities $ 277,221 $ 344,904  Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations without call or prepayment penalties.

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2018
Long-Term Debt [Abstract]
Long-Term Debt	  10. Long-Term Debt Debt, net of discounts and deferred financing costs, consists of the following:     March 31, 2018 December 31, 2017  (In thousands)  Long-term debt $ 359,449 $ 355,677  Less current portion - -  Long-term debt outstanding $ 359,449 $ 355,677  On July 6, 2016, the Company issued $460.0 million aggregate principal amount of 3.25% Convertible Senior Notes due 2023 (the “ Convertible Notes ”) . The Company received net proceeds of $447.6 million after deducting underwriting discounts and estimated offering expenses of approximately $12.4 million. The Company used approximately $38.4 million of the net proceeds from the offering to fund the payment of the cost of the C apped C all T ransactions (as defined below) that were entered into in connection with the issuance of the Convertible Notes. The Convertible Notes are senior unsecured obligations of the Company. Interest is payable semi-annually on January 1 and July 1 of each year, beginning on January 1, 2017. The Convertible Notes mature on July 1, 2023, unless earlier repurchased, redeemed or converted. The Convertible Notes are convertible at the option of holders, under certain circumstances and during certain periods, into cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock, at the Company’s election. The initial conversion rate of the Convertible Notes is 5.0358 shares of the Company’s common stock per $1,000 principal amount of Convertible Notes, which is equivalent to an initial conversion price of approximately $198.58 per share of the Company’s common stock. The conversion rate is subject to adjustment upon the occurrence of certain events. The Company may redeem for cash all or part of the Convertible Notes, at its option, on or after July 6, 2021 , under certain circumstances at a redemption price equal to 100% of the principal amount of the Convertible Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. On June 30, 2016, in connection with the pricing of the Convertible Notes, the Company entered into privately-negotiated capped call transactions (the “Base Capped Call Transactions”) with each of Royal Bank of Canada, UBS AG, London Branch, and Credit Suisse Capital LLC (the “Option Counterparties”). On July 1, 2016, in connection with the underwriters’ exercise of their over-allotment option in full, the Company entered into additional capped call transactions (the “Additional Capped Call Transactions” and, together with the Base Capped Call Transactions, the “Capped Call Transactions”) with the Option Counterparties. The Capped Call Transactions are expected generally to reduce the potential dilution upon conversion of the Convertible Notes in the event that the market price per share of the Company’s common stock, as measured under the terms of the Capped Call Transactions, is greater than the strike price of the Capped Call Transactions, which initially corresponds to the conversion price of the Convertible Notes, and is subject to anti-dilution adjustments generally similar to those applicable to the conversion rate of the Convertible Notes. The cap price of the Capped Call Transactions is initially $262.2725 per share, and is subject to certain adjustments under the terms of the Capped Call Transactions. If, however, the market price per share of the Company’s common stock, as measured under the terms of the Capped Call Transactions, exceeds the cap price of the Capped Call Transactions, there would nevertheless be dilution upon conversion of the Convertible Notes to the extent that such market price exceeds the cap price of the Capped Call Transactions . In accordance with ASC Subtopic 470-20, “Debt with Conversion and Other Options,” the Company used an effective interest rate of 8.4% to determine the liability component of the Convertible Notes. This resulted in the recognition of $334.4 million as the liability component of the Convertible Notes and the recognition of the residual $113.1 million as the debt discount with a corresponding increase to additional paid-in capital for the equity component of the Convertible Notes. Interest expense was $7.5 million and $7.2 million for the three months ended March 31, 2018 and 2017 , respectively, related to the Convertible Notes. Accrued interest on the Convertible Notes was approximately $3.7 million and $7.5 million as of March 31, 2018 and December 31, 2017 , respectively. The Company recorded debt issuance costs of $12.4 million, which are being amortized using the effective interest method. As of March 31, 2018 , $10.0 million of debt issuance costs are recorded on the unaudited condensed consolidated balance sheet in Long-Term Debt, in accordance with ASU 2015-0 3, Interest – Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. As of March 31, 2018 , $460.0 million aggregate principal amount of the Convertible Notes was outstanding .

Product Revenue, Net

Product Revenue, Net	3 Months Ended
	Mar. 31, 2018
Product Revenue, Net [Abstract]
Product Revenue, Net	    11. Product Revenue, Net  The Company recognized net sales of Ocaliva of $ 35.2 million and $20.6 million for the three months ended March 31, 2018 and 2017 , respectively. The table below summarizes consolidated product revenue, net by region:      Three Months Ended March 31,  2018 2017  (In thousands)  Product revenue, net:  U.S. $ 28,513 $ 19,777  ex-U.S. 6,645 826  Total product revenue, net $ 35,158 $ 20,603 

Stock Compensation

Stock Compensation	3 Months Ended
	Mar. 31, 2018
Stock Compensation [Abstract]
Stock Compensation	  12. Stock Compensation  The Company’s 2012 Equity Incentive Plan (“2012 Plan”) became effective upon the pricing of its initial public offering in October 2012. At the same time, the Company’s 2003 Stock Incentive Plan (“2003 Plan”) was terminated and 555,843 shares available under the 2003 Plan were added to the 2012 Plan.  On January 1, 2018, the number of shares available for future grants under the 2012 Plan increased by 1,010,693 shares, as a result of the automatic increase in shares reserved pursuant to the terms thereof .  The estimated fair value of the options that have been granted under the 2003 and 2012 Plans is determined utilizing the Black-Scholes option-pricing model at the date of grant. The fair value of restricted stock units (“RSUs”) and restricted share awards (“RSAs”) that have been granted under the 2012 Plan is determined utilizing the closing stock price on the date of grant. The fair value of the performance stock units (“PSUs”) and performance share awards (“PSAs”) granted in the three months ended March 31, 2018 is determined utilizing the Monte Carlo pricing model.  The following table summarizes stock option activity during the three months ended March 31, 2018 :         Weighted  Average  Number Weighted Remaining Aggregate  of Shares Average Contractual Intrinsic Value  (In thousands) Exercise Price Term (years) (In thousands)  Outstanding at December 31, 2017 1,808 $ 114.70 7.4 $ 14,648  Granted 561 $ 58.56 - $ -  Exercised (18) $ 25.57 - $ -  Cancelled/forfeited (98) $ 121.33 - $ -  Expired (23) $ 151.90 - $ -  Outstanding at March 31, 2018 2,230 $ 100.51 7.3 $ 17,057  Expected to vest 2,230 $ 100.51 7.3 $ 17,057  Exercisable 1,034 $ 107.14 5.3 $ 15,227  As of March 31, 2018 , there was approximately $52.4 million of total unrecognized compensation expense related to the unvested stock options shown in the table above, which is expected to be recognized over a weighted average period of 2.8 years.  The fair value of the Company's option awards were estimated using the assumptions below:     Three Months Ended March 31,  2018 2017  Volatility 60.9 - 60.9 60.9 - 65.4%  Expected term (in years) 6.0 -6.0 6.0 - 9.9  Risk-free rate 2.4 - 2.7% 2.0 - 2.4%  Expected dividend yield —% —%   The following table summarizes the aggregate RSU , PSU, PSA and RSA activity during the three months ended March 31, 2018 :      Weighted  Number of Average Fair  Awards Value  (In thousands)  Non-vested shares outstanding, December 31, 2017 493 $ 113.60  Granted 502 $ 58.50  Vested (97) $ 127.19  Forfeited (51) $ 111.58  Non-vested shares outstanding, March 31, 2018 847 $ 79.50  As of March 31, 2018 , there was approximately $59.8 million of total unrecognized compensation expense related to unvested RSUs , PSUs, PSAs and RSAs, which is expected to be recognized over a weighted average period of 2.8 years.  On February 5, 2018, the Company granted a total of 51,200 PSUs and 4,300 PSAs to certain of the Company’s executive officers. The performance criterion is based on the Total Shareholder Return (“TSR”) of the Company’s common stock relative to the TSR of the companies comprising the S&P Biotechnology Select Industry Index over a 3-year performance period and is accounted for as a market condition under ASC Topic 718, Compensation – Stock Compensation (“ASC Topic 718”). The TSR is calculated by dividing (a) the difference of the ending average minus the beginning average closing stock price by (b) the beginning average closing stock price. The beginning average stock price equals the average closing stock price over the one calendar month period prior to the beginning of the performance period. The ending average stock price equals the average closing price over the one calendar month period ending on the last day of the p erformance p eriod. The relative TSR is then used to calculate the payout percentage, which may range from zero percent (0%) to one hundred and fifty percent (150%) of the target award. The Company utilized a Monte Carlo Simulation to determine the grant date fair value of the awards. T he Company recorded approximately $169,000 of stock - based compensation related to PSUs and PSAs during the three months ended March 31, 2018.  The Company accounts for forfeitures when they occur. Ultimately, the actual expense recognized over the vesting period will be for only those shares that vest . When certain of the Company’s performance based grants (other than PSUs and PSAs) are issued, the Company recognizes no expense until achievement of the performance requirement is deemed probable.  Stock-based compensation expense has been reported in our statements of operations as follows:     Three Months Ended March 31,  2018 2017  (In thousands)  Selling, general and administrative $ 8,676 $ 8,974  Research and development 3,629 5,087  Total stock-based compensation $ 12,305 $ 14,061 

Net Loss Per Share

Net Loss Per Share	3 Months Ended
	Mar. 31, 2018
Net Loss Per Share [Abstract]
Net Loss Per Share	   13. Net Loss Per Share The following table presents the historical computation of basic and diluted net loss per share:        Three Months Ended March 31,  2018 2017  (In thousands, except per share amounts)  Historical net loss per share  Numerator:  Net loss attributable to common stockholders $ (81,590) $ (89,930)  Denominator:  Weighted average shares used in calculating net loss per share - basic and diluted 25,309 24,931   Net loss per share:  Basic and diluted $ (3.22) $ (3.61)  The following potentially dilutive securities have been excluded from the computations of diluted weighted average shares outstanding:         Three Months Ended March 31,  2018 2017  (In thousands)  Convertible Notes 2,316 2,316  Options 2,230 1,927  Restricted stock units 847 514  Total 5,393 4,757 

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	 1 4 . Subsequent Events  On April 9, 2018, the Company issued and sold (i) 2,695,313 shares of common stock in a registered public offering (including 351,563 shares issued and sold upon the exercise in full of the underwriters’ option to purchase additional shares), at a price to the public of $64.00 per share (the “Public Offering”) and (ii) 1,562,500 shares of common stock (the “Private Placement Shares”) in a private placement (the “Concurrent Private Placement”) exempt from the registration requirements of the Securities Act of 1933, as amended, at a purchase price per share equivalent to the price to the public set in the Public Offering and pursuant to a securities purchase agreement (the “Securities Purchase Agreement”) that the Company entered into with the purchasers in the Concurrent Private Placement (the “Private Placement Purchasers”). Pursuant to the Securities Purchase Agreement, the Company granted to the Private Placement Purchasers certain registration rights requiring the Company, upon request of the Private Placement Purchasers (and/or certain affiliate transferees thereof) on or after June 5, 2018 and subject to certain terms and conditions, to register the resale by such Private Placement Purchasers (and/or such affiliates) of the Private Placement Shares held by them. The net proceeds to the Company from the Public Offering and the Concurrent Private Placement were approximately $261.4 million, after deducting underwriting discounts, commissions and estimated offering expenses of approximately $11.1 million.

Basis of Presentation (Policy)

Basis of Presentation (Policy)	3 Months Ended
	Mar. 31, 2018
Overview of Business [Abstract]
Use of Estimates	Use of Estimates  The preparation of these unaudited consolidated condensed financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, expenses, revenues and related disclosures. Significant estimates include: clinical trial accruals, revenues and stock-based compensation expense. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions

Cash, Cash Equivalents and In22

Cash, Cash Equivalents and Investments (Tables)	3 Months Ended
	Mar. 31, 2018
Cash, Cash Equivalents, and Investments [Abstract]
Schedule of Available-for-sale Securities Reconciliation	The following table summarizes the Company’s cash, cash equivalents and investments as of March 31, 2018 and December 31, 2017 :    As of March 31, 2018  Gross Gross  Unrealized Unrealized  Amortized Cost Gains Losses Fair Value   (In thousands)  Cash and cash equivalents:  Cash and money market funds $ 48,871 $ - $ - $ 48,871  Investment securities:  Commercial paper 8,909 - (31) 8,878  Corporate debt securities 263,476 - (1,098) 262,378  U.S. government and agency securities 5,995 - (30) 5,965  Total investments 278,380 - (1,159) 277,221  Total cash, cash equivalents and investments $ 327,251 $ - $ (1,159) $ 326,092     As of December 31, 2017  Gross Gross  Unrealized Unrealized  Amortized Cost Gains Losses Fair Value   (In thousands)  Cash and cash equivalents:  Cash and money market funds $ 70,013 $ - $ - $ 70,013  Investment securities:  Commercial paper 2,986 - (3) 2,983  Corporate debt securities 333,958 - (752) 333,206  U.S. government and agency securities 8,743 - (28) 8,715  Total investments 345,687 - (783) 344,904  Total cash, cash equivalents and investments $ 415,700 $ - $ (783) $ 414,917 

Fixed Assets, Net (Tables)

Fixed Assets, Net (Tables)	3 Months Ended
	Mar. 31, 2018
Fixed Assets, Net [Abstract]
Fixed Assets, Net	Fixed assets are stated at cost and depreciated or amortized using the straight-line method based on useful lives as follows:      Useful lives  (Years) March 31, 2018 December 31, 2017  (In thousands)  Office equipment and software 3 $ 4,049 $ 5,048  Leasehold improvements Over life of lease 14,722 14,665  Furniture and fixtures 7 4,334 5,257  Subtotal 23,105 24,970  Less: accumulated depreciation (9,031) (8,786)  Fixed assets, net $ 14,074 $ 16,184 

Inventory, Net (Tables)

Inventory, Net (Tables)	3 Months Ended
	Mar. 31, 2018
Inventory, Net [Abstract]
Schedule of Inventory	Inventories are stated at the lower of cost or market. Inventories consist ed of the following:    March 31, 2018 December 31, 2017  (In thousands)  Work-in-process $ 7,713 $ 3,249  Finished goods 225 231  Inventory, net $ 7,938 $ 3,480 

Accounts Payable, Accrued Exp25

Accounts Payable, Accrued Expenses and Other Liabilities (Tables)	3 Months Ended
	Mar. 31, 2018
Accounts Payable, Accrued Expenses and Other Liabilities [Abstract]
Schedule of Accounts Payable and Accrued Liabilities	Accounts payable, accrued expenses and other liabilities consisted of the following:    March 31, 2018 December 31, 2017  (In thousands)  Accounts payable $ 13,545 $ 6,965  Accrued contracted services 37,984 51,154  Accrued employee compensation 11,600 27,118  Other liabilities 10,958 9,540  Accounts payable, accrued expenses and other liabilities $ 74,087 $ 94,777 

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Measurements [Abstract]
Fair Value, Marketable Securities Measured on Recurring and Nonrecurring Basis	  Financial assets carried at fair value are classified in the tables below in one of the three categories described above:         Fair Value Measurements Using  Total Level 1 Level 2 Level 3  (In thousands)  March 31, 2018  Assets:  Money market funds (included in cash and cash equivalents) $ 10,239 $ 10,239 $ - $ -  Available for sale securities:  Commercial paper 8,878 - 8,878 -  Corporate debt securities 262,378 - 262,378 -  U.S. government and agency securities 5,965 - 5,965 -  Total financial assets: $ 287,460 $ 10,239 $ 277,221 $ -   December 31, 2017  Assets:  Money market funds (included in cash and cash equivalents) $ 13,361 $ 13,361 $ - $ -  Available for sale securities:  Commercial paper 2,983 - 2,983 -  Corporate debt securities 333,206 - 333,206 -  U.S. government and agency securities 8,715 - 8,715 -  Total financial assets $ 358,265 $ 13,361 $ 344,904 $ - 
Schedule of Available for Sale Securities Debt Maturities	  Fair Value Measurements Using  Total Level 1 Level 2 Level 3  (In thousands)  March 31, 2018  Assets:  Money market funds (included in cash and cash equivalents) $ 10,239 $ 10,239 $ - $ -  Available for sale securities:  Commercial paper 8,878 - 8,878 -  Corporate debt securities 262,378 - 262,378 -  U.S. government and agency securities 5,965 - 5,965 -  Total financial assets: $ 287,460 $ 10,239 $ 277,221 $ -   December 31, 2017  Assets:  Money market funds (included in cash and cash equivalents) $ 13,361 $ 13,361 $ - $ -  Available for sale securities:  Commercial paper 2,983 - 2,983 -  Corporate debt securities 333,206 - 333,206 -  U.S. government and agency securities 8,715 - 8,715 -  Total financial assets $ 358,265 $ 13,361 $ 344,904 $ - The estimated fair value of marketable debt securities (commercial paper, corporate debt securities and U.S. government and agency securities), by contractual maturity, are as follows:       Fair Value as of  March 31, 2018 December 31, 2017  (In thousands)  Due in one year or less $ 222,895 $ 282,159  Due after 1 year through 2 years 54,326 62,745  Total investments in debt securities $ 277,221 $ 344,904 

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2018
Long-Term Debt [Abstract]
Schedule of Long-term Debt Instruments	Debt, net of discounts and deferred financing costs, consists of the following:     March 31, 2018 December 31, 2017  (In thousands)  Long-term debt $ 359,449 $ 355,677  Less current portion - -  Long-term debt outstanding $ 359,449 $ 355,677 

Product Revenue, Net (Tables)

Product Revenue, Net (Tables)	3 Months Ended
	Mar. 31, 2018
Product Revenue, Net [Abstract]
Schedule of Product Revenue, Net	The table below summarizes consolidated product revenue, net by region:      Three Months Ended March 31,  2018 2017  (In thousands)  Product revenue, net:  U.S. $ 28,513 $ 19,777  ex-U.S. 6,645 826  Total product revenue, net $ 35,158 $ 20,603 

Stock Compensation (Tables)

Stock Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Stock Compensation [Abstract]
Schedule of Share Based Compensation Stock Options Activities	The following table summarizes stock option activity during the three months ended March 31, 2018 :         Weighted  Average  Number Weighted Remaining Aggregate  of Shares Average Contractual Intrinsic Value  (In thousands) Exercise Price Term (years) (In thousands)  Outstanding at December 31, 2017 1,808 $ 114.70 7.4 $ 14,648  Granted 561 $ 58.56 - $ -  Exercised (18) $ 25.57 - $ -  Cancelled/forfeited (98) $ 121.33 - $ -  Expired (23) $ 151.90 - $ -  Outstanding at March 31, 2018 2,230 $ 100.51 7.3 $ 17,057  Expected to vest 2,230 $ 100.51 7.3 $ 17,057  Exercisable 1,034 $ 107.14 5.3 $ 15,227 
Schedule of Share Based Compensation Arrangement By Share Based Payment Award Grants in Period Fair Value Assumptions	The fair value of the Company's option awards were estimated using the assumptions below:     Three Months Ended March 31,  2018 2017  Volatility 60.9 - 60.9 60.9 - 65.4%  Expected term (in years) 6.0 -6.0 6.0 - 9.9  Risk-free rate 2.4 - 2.7% 2.0 - 2.4%  Expected dividend yield —% —% 
Schedule of Share-based Compensation, Restricted Stock Units Award Activity	The following table summarizes the aggregate RSU , PSU, PSA and RSA activity during the three months ended March 31, 2018 :      Weighted  Number of Average Fair  Awards Value  (In thousands)  Non-vested shares outstanding, December 31, 2017 493 $ 113.60  Granted 502 $ 58.50  Vested (97) $ 127.19  Forfeited (51) $ 111.58  Non-vested shares outstanding, March 31, 2018 847 $ 79.50 
Schedule of Stock Based Compensation Expense	Stock-based compensation expense has been reported in our statements of operations as follows:     Three Months Ended March 31,  2018 2017  (In thousands)  Selling, general and administrative $ 8,676 $ 8,974  Research and development 3,629 5,087  Total stock-based compensation $ 12,305 $ 14,061 

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Net Loss Per Share [Abstract]
Schedule of Calculation of Numerator and Denominator in Earnings Per Share	The following table presents the historical computation of basic and diluted net loss per share:        Three Months Ended March 31,  2018 2017  (In thousands, except per share amounts)  Historical net loss per share  Numerator:  Net loss attributable to common stockholders $ (81,590) $ (89,930)  Denominator:  Weighted average shares used in calculating net loss per share - basic and diluted 25,309 24,931   Net loss per share:  Basic and diluted $ (3.22) $ (3.61) 
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The following potentially dilutive securities have been excluded from the computations of diluted weighted average shares outstanding:         Three Months Ended March 31,  2018 2017  (In thousands)  Convertible Notes 2,316 2,316  Options 2,230 1,927  Restricted stock units 847 514  Total 5,393 4,757 

Summary of Significant Accoun31

Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Mar. 31, 2018	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2017	Dec. 31, 2017
Product revenue, Ocaliva	$ 35,158		$ 20,603
Additional paid-in capital	$ 1,499,476				$ 1,486,690
Ocaliva [Member]
Reserves related to future returns		$ 700
Ocaliva [Member] | Adjustment to Recognition of Previously Deferred Revenue [Member]
Product revenue, Ocaliva				$ 4,100

Significant Agreements (Narrati

Significant Agreements (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		12 Months Ended
	May 31, 2014	Mar. 31, 2011	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Significant Agreements [Line Items]
License arrangement, deferred revenue, recognized			$ 800	$ 400
Security deposit			7,961		$ 16,376
Licensing revenue			805	$ 445
Milestone Payment [Member] | Dainippon Sumitomo Pharma Co Ltd [Member]
Significant Agreements [Line Items]
License arrangement, deferred revenue, recognized			3,600		$ 4,500
Nonsoftware License Arrangement [Member] | Dainippon Sumitomo Pharma Co Ltd [Member]
Significant Agreements [Line Items]
Development milestone reached			6,000
Nonsoftware License Arrangement [Member] | Intellectual Property [Member]
Significant Agreements [Line Items]
License arrangement, deferred revenue, recognized			400
Nonsoftware License Arrangement [Member] | Up-front Payment [Member] | Dainippon Sumitomo Pharma Co Ltd [Member]
Significant Agreements [Line Items]
License agreement payment		$ 15,000
Nonsoftware License Arrangement [Member] | Additional Development Receivable [Member] | Dainippon Sumitomo Pharma Co Ltd [Member]
Significant Agreements [Line Items]
Contingent arrangement receivable amount			$ 23,000
Korea [Member] | Nonsoftware License Arrangement [Member] | Up-front Payment [Member] | Dainippon Sumitomo Pharma Co Ltd [Member]
Significant Agreements [Line Items]
License agreement payment	$ 1,000

Cash, Cash Equivalents and In33

Cash, Cash Equivalents and Investments (Schedule of Available-for-sale Securities Reconciliation) (Details) $ in Thousands	Mar. 31, 2018USD ($)security	Dec. 31, 2017USD ($)
Investments:
Total investments, Amortized Cost	$ 278,380	$ 345,687
Total cash and cash equivalents and investments, Amortized Cost	327,251	415,700
Total investments, Gross Unrealized Losses	(1,159)	(783)
Total cash and cash equivalents and investments, Gross Unrealized Losses	(1,159)	(783)
Total investments, Fair Value	277,221	344,904
Total cash and cash equivalents and investments, Fair Value	$ 326,092	414,917
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security	19
Commercial Paper [Member]
Investments:
Total investments, Amortized Cost	$ 8,909	2,986
Total investments, Gross Unrealized Losses	(31)	(3)
Total investments, Fair Value	8,878	2,983
Corporate Debt Securities [Member]
Investments:
Total investments, Amortized Cost	263,476	333,958
Total investments, Gross Unrealized Losses	(1,098)	(752)
Total investments, Fair Value	262,378	333,206
Us Government Agencies Debt Securities [Member]
Investments:
Total investments, Amortized Cost	5,995	8,743
Total investments, Gross Unrealized Losses	(30)	(28)
Total investments, Fair Value	5,965	8,715
Cash and Money Market Funds [Member]
Cash and cash equivalents:
Cash and Cash Equivalents, Amortized Cost	48,871	70,013
Cash and cash equivalents, Fair Value	$ 48,871	$ 70,013

Fixed Assets, Net (Fixed Assets

Fixed Assets, Net (Fixed Assets Stated at Cost) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Fixed assets	$ 23,105	$ 24,970
Less: accumulated depreciation	(9,031)	(8,786)
Fixed assets, net	14,074	16,184
Office Equipment [Member]
Fixed assets	$ 4,049	5,048
Property, Plant and Equipment, Useful Life	3 years
Leasehold Improvements [Member]
Fixed assets	$ 14,722	14,665
Property, Plant and Equipment, Estimated Useful Lives	Over life of lease
Furniture and Fixtures [Member]
Fixed assets	$ 4,334	$ 5,257
Property, Plant and Equipment, Useful Life	7 years

Inventory (Schedule of Inventor

Inventory (Schedule of Inventory) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Inventory, Net [Abstract]
Work-in-process	$ 7,713	$ 3,249
Finished goods	225	231
Inventory, net	$ 7,938	$ 3,480

Accounts Payable, Accrued Exp36

Accounts Payable, Accrued Expenses and Other Liabilities (Schedule of Accounts Payable and Accrued Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts Payable, Accrued Expenses and Other Liabilities [Abstract]
Accounts payable	$ 13,545	$ 6,965
Accured contracted services	37,984	51,154
Accrued employee compensation	11,600	27,118
Other liabilities	10,958	9,540
Accounts payable, accrued expenses and other liabilities	$ 74,087	$ 94,777

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value, Marketable Securities Measured on Recurring and Nonrecurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Available-For-Sale Securities, Fair Value Disclosure	$ 277,221	$ 344,904
Total financial assets	287,460	358,265
Fair Value, Inputs, Level 1 [Member]
Total financial assets	10,239	13,361
Fair Value, Inputs, Level 2 [Member]
Total financial assets	277,221	344,904
Fair Value, Inputs, Level 3 [Member]
Total financial assets
Money Market Funds [Member]
Cash and cash equivalents, fair value disclosure	10,239	13,361
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents, fair value disclosure	10,239	13,361
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents, fair value disclosure
Commercial Paper [Member]
Available-For-Sale Securities, Fair Value Disclosure	8,878	2,983
Commercial Paper [Member] | Fair Value, Inputs, Level 2 [Member]
Available-For-Sale Securities, Fair Value Disclosure	8,878	2,983
Commercial Paper [Member] | Fair Value, Inputs, Level 3 [Member]
Available-For-Sale Securities, Fair Value Disclosure
Corporate Debt Securities [Member]
Available-For-Sale Securities, Fair Value Disclosure	262,378	333,206
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-For-Sale Securities, Fair Value Disclosure	262,378	333,206
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-For-Sale Securities, Fair Value Disclosure
Us Government Agencies Debt Securities [Member]
Available-For-Sale Securities, Fair Value Disclosure	5,965	8,715
Us Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available-For-Sale Securities, Fair Value Disclosure	5,965	8,715
Us Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available-For-Sale Securities, Fair Value Disclosure

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule of Available for Sale Securities Debt Maturities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Total investments in debt securities	$ 277,221	$ 344,904
Debt Securities [Member]
Due in one year or less	222,895	282,159
Due after 1 year through 5 years	54,326	62,745
Total investments in debt securities	$ 277,221	$ 344,904

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details)	Feb. 05, 2018shares	Jul. 06, 2016USD ($)$ / shares	Mar. 31, 2018USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)	Jun. 30, 2016$ / shares
Payments for capped call transactions and associated costs		$ 38,400,000
Debt instrument liability component effective interest rate			8.40%
Long-term debt			$ 359,449,000		$ 355,677,000
Interest expense			7,509,000	$ 7,207,000
Amortization of debt issuance costs			12,400,000
PSUs granted during period | shares	51,200
Stock-based compensation, PSUs			169,000
Convertible Senior Notes 3.25% [Member] | Convertible Debt [Member]
Debt instrument, face amount		460,000,000
Proceeds from convertible debt		447,600,000
Debt issuance costs		$ 12,400,000	$ 10,000,000
Debt instrument, convertible, conversion ratio		5.0358
Debt instrument, convertible, conversion price | $ / shares		$ 198.58
Debt instrument, convertible, earliest date			Jul. 6, 2021
Debt instrument, redemption price, percentage			100.00%
Long-term debt		$ 334,400,000
Convertible debt, outstanding			$ 460,000,000
Debt instrument, unamortized discount, noncurrent		$ 113,100,000
Interest expense			7,500,000	$ 7,200,000
Interest payable, current			$ 3,700,000		$ 7,500,000
Capped Call Transactions [Member]
Cap price of capped call transaction | $ / shares						$ 262.2725

Long-Term Debt (Schedule of Lon

Long-Term Debt (Schedule of Long-term Debt Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Long-Term Debt [Abstract]
Long-term Debt, Total	$ 359,449	$ 355,677
Less current portion
Long-term debt outstanding	$ 359,449	$ 355,677

Product Revenue, Net (Narrative

Product Revenue, Net (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Product Revenue, Net [Abstract]
Product revenue, net	$ 35,158	$ 20,603

Product Revenue, Net (Schedule

Product Revenue, Net (Schedule of Product Revenue, Net) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Product revenue, net	$ 35,158	$ 20,603
Product [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Product revenue, net	35,158	20,603
Product [Member] | United States [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Product revenue, net	28,513	19,777
Product [Member] | Non-US [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Product revenue, net	$ 6,645	$ 826

Stock Compensation (Narrative)

Stock Compensation (Narrative) (Details) - USD ($)	Feb. 05, 2018	Jan. 01, 2018	Oct. 31, 2012	Mar. 31, 2018	Mar. 31, 2017
Share-based compensation not yet recognized, options				$ 52,400,000
PSUs granted during period	51,200
Stock-based compensation, PSUs				$ 169,000
2012 Stock Plan [Member]
Additional shares available		1,010,693	555,843
Stock Options [Member]
Fair value assumption method used				Black-Scholes option-pricing model
Share-based compensation not yet recognized, period				2 years 9 months 18 days
Restricted Stock [Member]
Share-based compensation not yet recognized, other than options				$ 59,800,000
Share-based compensation not yet recognized, period					2 years 9 months 18 days
PSA [Member]
PSUs granted during period	4,300

Stock Compensation (Schedule of

Stock Compensation (Schedule of Share Based Compensation Stock Options Activities) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Stock Compensation [Abstract]
Beginning Outstanding, Number of Shares	1,808
Granted - Number of Shares	561
Exercised - Number of Shares	(18)
Forfeited - Number of Shares	(98)
Expired - Number of Shares	(23)
Ending Outstanding, Number of Shares	2,230	1,808
Expected to vest - Number of shares	2,230
Exercisable - Number of Shares	1,034
Beginning Outstanding, Weighted Average Exercise Price	$ 114.70
Granted - Weighted Average Exercise Price	58.56
Exercised - Weighted Average Exercise Price	25.57
Forfeited - Weighted Average Exercise Price	121.33
Expired - Weighted Average Exercise Price	151.90
Ending Outstanding, Weighted Average Exercise Price	100.51	$ 114.70
Expected to vest - Weighted Average Exercise Price	100.51
Exercisable - Weighted Average Exercise Price	$ 107.14
Options Outstanding - Weighted Average Remaining Life	7 years 3 months 18 days	7 years 4 months 24 days
Expected to vest - Weighted Average Remaining Term	7 years 3 months 18 days
Exercisable - Weighted Average Remaining Term	5 years 3 months 18 days
Options Outstanding - Aggregate Intrinsic Value	$ 17,057	$ 14,648
Expected to vest - Aggregate Intrinsic Value	17,057
Exercisable - Aggregate Intrinsic Value	$ 15,227

Stock Compensation (Schedule 45

Stock Compensation (Schedule of Share Based Compensation Arrangement By Share Based Payment Award Grants in Period Fair Value Assumptions) (Details) - Stock Options [Member]	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value assumption method used	Black-Scholes option-pricing model
Volatility	60.90%
Volatility, minimum		60.90%
Volatility, maximum		65.40%
Expected term (in years)	6 years
Risk-free interest rate, minimum	2.40%	2.00%
Risk-free interest rate, maximum	2.70%	2.40%
Expected dividend yield
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)		6 years
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)		9 years 10 months 24 days

Stock Compensation (Schedule 46

Stock Compensation (Schedule of Share-based Compensation, Restricted Stock Units and Award Activity) (Details) shares in Thousands	3 Months Ended
	Mar. 31, 2018$ / sharesshares
Stock Compensation [Abstract]
Outstanding, December 31, 2016 | shares	493
Granted - Shares | shares	502
Vested - Shares | shares	(97)
Forfeited - Shares | shares	(51)
Outstanding, September 30, 2017 | shares	847
Outstanding - Weighted Average Fair Value, December 31, 2016 | $ / shares	$ 113.60
Granted - Weighted Average Fair Value | $ / shares	58.50
Vested - Weighted Average Fair Value | $ / shares	127.19
Forfeited - Weighted Average Fair Value | $ / shares	111.58
Outstanding - Weighted Average Fair Value, September 30, 2017 | $ / shares	$ 79.50

Stock Compensation (Schedule 47

Stock Compensation (Schedule of Stock Based Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated stock-based compensation	$ 12,305	$ 14,061
Selling, General and Administrative Expenses [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated stock-based compensation	8,676	8,974
Research and Development Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated stock-based compensation	$ 3,629	$ 5,087

Net Loss Per Share (Schedule of

Net Loss Per Share (Schedule of Calculation of Numerator and Denominator in Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Numerator:
Net loss attributable to common stockholders	$ (81,590)	$ (89,930)
Denominator:
Weighted average shares used in calculating net loss per share - basic and diluted	25,309	24,931
Net loss per share, basic and diluted (in dollars per share)	$ (3.22)	$ (3.61)

Net Loss Per Share (Schedule 49

Net Loss Per Share (Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share) (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Antidilutive securities excluded from computation of earnings per share, amount	5,393	4,757
Convertible Notes [Member]
Antidilutive securities excluded from computation of earnings per share, amount	2,316	2,316
Stock Options [Member]
Antidilutive securities excluded from computation of earnings per share, amount	2,230	1,927
Restricted Stock Units (RSUs) [Member]
Antidilutive securities excluded from computation of earnings per share, amount	847	514

Subsequent Events (Details)

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 09, 2018	Jan. 01, 2018	Oct. 31, 2012
Subsequent Event [Member]
Proceeds from issuance	$ 261.4
Issuance costs	$ 11.1
Common Stock [Member] | Subsequent Event [Member]
Sale of stock in offering	2,695,313
Sale of stock, price per share	$ 64
Private Placement [Member] | Subsequent Event [Member]
Sale of stock in offering	1,562,500
Underwriters' Shares [Member] | Subsequent Event [Member]
Sale of stock in offering	351,563
2012 Stock Plan [Member]
Additional shares available		1,010,693	555,843