Neurocrine Biosciences (NBIX) 10-Q 1 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 27, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Trading Symbol	NBIX
Entity Registrant Name	NEUROCRINE BIOSCIENCES INC
Entity Central Index Key	914,475
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		88,493,045

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 267,818	$ 83,267
Short-term investments, available-for-sale	243,200	224,083
Accounts receivable	29,818	0
Inventory	242	0
Other current assets	7,407	3,092
Total current assets	548,485	310,442
Property and equipment, net	9,140	6,271
Long-term investments, available-for-sale	210,258	43,490
Restricted cash	4,613	4,883
Total assets	772,496	365,086
Current liabilities:
Accounts payable and accrued liabilities	37,289	26,182
Current portion of cease-use liability	121	236
Current portion of deferred rent	0	470
Current portion of deferred gain on sale of real estate	731	3,526
Total current liabilities	38,141	30,414
Deferred gain on sale of real estate	8,226	7,372
Deferred revenue	10,231	10,231
Deferred rent	3,163	1,462
Convertible senior notes	365,110	0
Cease-use liability	0	617
Other liabilities	113	113
Total liabilities	424,984	50,209
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares issued and outstanding	0	0
Common stock, $0.001 par value; 220,000,000 shares authorized; issued and outstanding shares were 88,462,002 as of September 30, 2017 and 86,883,300 as of December 31, 2016	88	87
Additional paid-in capital	1,553,718	1,371,432
Accumulated other comprehensive loss	(534)	(318)
Accumulated deficit	(1,205,760)	(1,056,324)
Total stockholders' equity	347,512	314,877
Total liabilities and stockholders' equity	$ 772,496	$ 365,086

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	220,000,000	220,000,000
Common stock, shares issued	88,462,002	86,883,300
Common stock, shares outstanding	88,462,002	86,883,300

Condensed Consolidated Statemen

Condensed Consolidated Statements of Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues:
Product sales, net	$ 45,774	$ 0	$ 52,109	$ 0
License fees and milestones	15,000	0	15,000	15,000
Total revenues	60,774	0	67,109	15,000
Operating expenses:
Cost of product sales	433	0	494	0
Research and development	22,463	20,942	96,213	71,708
Sales, general and administrative	43,873	17,494	113,597	44,413
Total operating expenses	66,769	38,436	210,304	116,121
Loss from operations	(5,995)	(38,436)	(143,195)	(101,121)
Other (expense) income, net:
Gain/(loss) on sale/disposal of assets	5	(9)	7	8
Deferred gain on real estate	183	853	1,941	2,560
Interest expense	(7,337)	0	(12,104)	0
Investment income, net	2,019	705	3,915	2,122
Total other (expense) income	(5,130)	1,549	(6,241)	4,690
Net loss	$ (11,125)	$ (36,887)	$ (149,436)	$ (96,431)
Net loss per common share:
Basic and diluted	$ (0.13)	$ (0.43)	$ (1.70)	$ (1.11)
Shares used in the calculation of net loss per common share:
Basic and diluted	88,325	86,784	87,894	86,659
Other comprehensive loss:
Net loss	$ (11,125)	$ (36,887)	$ (149,436)	$ (96,431)
Net unrealized gains/(losses) on available-for-sale securities	179	(148)	(216)	790
Comprehensive loss	$ (10,946)	$ (37,035)	$ (149,652)	$ (95,641)

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (149,436)	$ (96,431)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,694	1,008
Gain on sale of assets	(1,948)	(2,568)
Deferred rent	1,231	(208)
Cease-use expense	(544)	(584)
Amortization of debt issuance costs	526	0
Amortization of debt discount	6,755	0
Amortization of premiums on investments	1,202	3,151
Non-cash share-based compensation expense	29,070	20,511
Change in operating assets and liabilities:
Accounts receivable	(29,818)	0
Inventory	(242)	0
Other current assets	(4,315)	34
Accounts payable and accrued liabilities	11,107	878
Cease-use liability	(188)	(239)
Other non-current liabilities	0	(108)
Net cash used in operating activities	(134,906)	(74,556)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of investments	(444,538)	(217,141)
Sales and maturities of investments	257,235	318,776
Proceeds from sales of property and equipment	7	13
Deposits and restricted cash	270	(92)
Purchases of property and equipment	(4,563)	(3,761)
Net cash (used in) provided by investing activities	(191,589)	97,795
CASH FLOWS FROM FINANCING ACTIVITIES
Issuance of common stock	8,265	2,327
Proceeds from issuance of senior convertible notes, net	502,781
Net cash provided by financing activities	511,046	2,327
Net increase in cash and cash equivalents	184,551	25,566
Cash and cash equivalents at beginning of the period	83,267	74,195
Cash and cash equivalents at end of the period	267,818	99,761
Supplemental Cash Flow Information
Cash paid for interest during the period	$ 0	$ 0

ORGANIZATION AND SIGNIFICANT AC

ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES	1. ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES Description of Business. ® catechol-O-methyltransferase Basis of Presentation 10-Q 10-01 S-X. These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2016 included in the Company’s Annual Report on Form 10-K Impact of Recently Issued Accounting Standards The Company does not anticipate the new standard having a material impact on currently reported net product sales. The Company is also currently evaluating the impact of the new standard on historical revenue recorded for its two collaboration agreements. This ongoing evaluation is dependent upon the resolution of certain questions relating to the application of, and transition to, the new revenue recognition guidance for collaboration agreements which will ultimately determine the adoption method and the ultimate impact the adoption of this standard will have on the Company’s consolidated financial statements. Based on the Company’s current assessment of the effect of the new standard on historical revenue under its collaboration agreements that is related to contingent payments, which are not dependent on its performance, the Company believes revenue could potentially be recognized earlier than historically recorded if information is available to allow the Company to record the payments without the risk of a future reversal. In February 2016, the FASB issued Accounting Standards Update (ASU) 2016-02 In November 2016, the FASB issued ASU 2016-18, beginning-of-period end-of-period beginning-of-period end-of-period Use of Estimates

PRODUCT SALES, NET

PRODUCT SALES, NET	9 Months Ended
	Sep. 30, 2017
Revenue from Contract with Customer [Abstract]
PRODUCT SALES, NET	2. PRODUCT SALES, NET Revenue Recognition Policy. INGREZZA was approved by the FDA on April 11, 2017 and the Company commenced shipments of INGREZZA to select pharmacies (SPs) and a select distributor (SD) in late April 2017. The SPs dispense product to a patient based on the fulfillment of a prescription and the SD sells product to government facilities, long-term care pharmacies or in-patient The Company has determined it can reasonably estimate its allowances for rebates and chargebacks at the time title and risk of loss transfers to the SP or SD. Therefore, the Company records revenue when the product is delivered to the SPs or SD, which is an approach frequently referred to as the “sell-in” The Company recognizes revenue from product sales net of the following allowances: Distribution Fees: Rebates: Chargebacks: Co-Payment co-payment Co-payment Product Returns:

REVENUE RECOGNITION FOR SIGNIFI

REVENUE RECOGNITION FOR SIGNIFICANT COLLABORATIVE RESEARCH AND DEVELOPMENT AGREEMENTS	9 Months Ended
	Sep. 30, 2017
Text Block [Abstract]
REVENUE RECOGNITION FOR SIGNIFICANT COLLABORATIVE RESEARCH AND DEVELOPMENT AGREEMENTS	3. REVENUE RECOGNITION FOR SIGNIFICANT COLLABORATIVE RESEARCH AND DEVELOPMENT AGREEMENTS Revenue Recognition Policy. Since 2011, the Company has followed the Accounting Standards Codification (ASC) for Revenue Recognition—Multiple-Element Arrangements, if applicable, to determine the recognition of revenue under license and collaboration agreements. The terms of these agreements generally contain multiple elements, or deliverables, which may include (i) licenses to the Company’s intellectual property, (ii) materials and technology, (iii) pharmaceutical supply, (iv) participation on joint development or joint steering committees, and (v) development services. The payments the Company receives under these arrangements typically include one or more of the following: up-front The ASC provides guidance relating to the separation of deliverables included in an arrangement into different units of accounting and the allocation of consideration to the units of accounting. The evaluation of multiple-element arrangements requires management to make judgments about (i) the identification of deliverables, (ii) whether such deliverables are separable from the other aspects of the contractual relationship, (iii) the estimated selling price of each deliverable, and (iv) the expected period of performance for each deliverable. To determine the units of accounting under a multiple-element arrangement, management evaluates certain separation criteria, including whether the deliverables have stand-alone value, based on the relevant facts and circumstances for each arrangement. The selling prices of deliverables under an arrangement may be derived using vendor specific objective evidence (VSOE), third-party evidence, or a best estimate of selling price (BESP), if VSOE or third-party evidence is not available. For most pharmaceutical licensing and collaboration agreements, BESP is utilized. The objective of BESP is to determine the price at which the Company would transact a sale if the element within the agreement was sold on a standalone basis. Establishing BESP involves management’s judgment and considers multiple factors, including market conditions and company-specific factors, including those factors contemplated in negotiating the agreements, as well as internally developed models that include assumptions related to market opportunity, discounted cash flows, estimated development costs, probability of success and the time needed to commercialize a product candidate pursuant to the agreement. In validating the BESP, management considers whether changes in key assumptions used to determine the BESP will have a significant effect on the allocation of the arrangement consideration between the multiple deliverables. The allocated consideration for each unit of accounting is recognized over the related obligation period in accordance with the applicable revenue recognition criteria. If there are deliverables in an arrangement that are not separable from other aspects of the contractual relationship, they are treated as a combined unit of accounting, with the allocated revenue for the combined unit recognized in a manner consistent with the revenue recognition applicable to the final deliverable in the combined unit. Payments received prior to satisfying the relevant revenue recognition criteria are recorded as unearned revenue in the accompanying balance sheets and recognized as revenue when the related revenue recognition criteria are met. The Company typically receives up-front For payments payable on achievement of milestones that do not meet all of the conditions to be considered substantive, the Company recognizes the portion of the payment allocable to delivered items as revenue when the specific milestone is achieved, and the contingency is removed. Prior to the revised multiple element guidance described above, adopted by the Company on January 1, 2011, upfront, nonrefundable payments for license fees, grants, and advance payments for sponsored research revenues received in excess of amounts earned were classified as deferred revenue and recognized as income over the contract or development period. Revenues from development milestones are accounted for in accordance with the Revenue Recognition – Milestone Method Topic of the FASB ASC (Milestone Method). Milestones are recognized when earned, as evidenced by written acknowledgment from the collaborator or other persuasive evidence that the milestone has been achieved, provided that the milestone event is substantive. A milestone event is considered to be substantive if its achievability was not reasonably assured at the inception of the agreement and the Company’s efforts led to the achievement of the milestone or the milestone was due upon the occurrence of a specific outcome resulting from the Company’s performance. The Company assesses whether a milestone is substantive at the inception of each agreement. Mitsubishi Tanabe Pharma Corporation (Mitsubishi Tanabe). (NBI-98854) up-front Under the terms of the Company’s agreement with Mitsubishi Tanabe, the collaboration effort between the parties to advance valbenazine towards commercialization in Japan and other select Asian markets is governed by a joint steering committee and joint development committee with representatives from both the Company and Mitsubishi Tanabe. There are no performance, cancellation, termination or refund provisions in the agreement that would have a material financial consequence to the Company. The Company does not directly control when event-based payments will be achieved or when royalty payments will begin. Mitsubishi Tanabe may terminate the agreement at its discretion upon 180 days’ written notice to the Company. In such event, all valbenazine product rights for Japan and other select Asian markets would revert to the Company. The Company has identified the following deliverables associated with the Mitsubishi Tanabe agreement: valbenazine technology license and existing know-how, As discussed above, the BESP method required the use of significant estimates. The Company used an income approach to estimate the selling price for the technology license and an expense approach for estimating development activities and the manufacture of pharmaceutical products. The development activities and the manufacture of pharmaceutical products are expected to be delivered throughout the duration of the agreement. The technology license and existing know-how During the first quarter of 2015, the Company recognized revenue under this agreement of $19.8 million associated with the delivery of a technology license and existing know-how. million up-front up-front non-contingent The Company evaluated the event-based payments under the Milestone Method and concluded only one immaterial event-based payment represents a substantive milestone. Event-based payments will be recognized when earned. During the third quarter of 2017, the Company recognized $15 million in development event-based payments resulting from Mitsubishi Tanabe’s initiation of Phase II/III development of valbenazine in tardive dyskinesia in Asia. The Company is eligible to receive from Mitsubishi Tanabe tiered royalty payments based on product sales in Japan and other select Asian markets. Royalties will be recognized as earned in accordance with the terms of the agreement, when product sales are reported by Mitsubishi Tanabe, the amount can be reasonably estimated, and collectability is reasonably assured. AbbVie Inc. (AbbVie) . Under the terms of the agreement, AbbVie is responsible for all third-party development, marketing and commercialization costs. The Company will be entitled to a percentage of worldwide sales of GnRH Compounds for the longer of ten years or the life of the related patent rights. AbbVie may terminate the collaboration at its discretion upon 180 days’ written notice to the Company. In such event, the Company would be entitled to specified payments for ongoing clinical development and related activities and all GnRH Compound product rights would revert to the Company. During the first quarter of 2016, the Company recognized $15 million in development event-based payments resulting from AbbVie initiating Phase III development of elagolix in uterine fibroids.

INVENTORY AND COST OF PRODUCT S

INVENTORY AND COST OF PRODUCT SALES	9 Months Ended
	Sep. 30, 2017
Inventory Disclosure [Abstract]
INVENTORY AND COST OF PRODUCT SALES	4. INVENTORY AND COST OF PRODUCT SALES Inventory is stated at the lower of cost or estimated net realizable value. The Company currently uses actual costing to determine the cost basis for its inventory. Inventory is valued on a first-in, first-out Prior to FDA approval of INGREZZA, all costs related to its manufacturing were charged to research and development expense in the period incurred. At September 30, 2017, the Company’s physical inventory included active pharmaceutical product that had been produced prior to FDA approval of INGREZZA and accordingly has no cost basis as the cost associated with producing this material was expensed rather than capitalized in accordance with authoritative guidance. Additionally, manufacturing of bulk drug product, finished bottling and other labeling activities that occurred post FDA approval are included in the inventory value at September 30, 2017. The Company provides reserves for potential excess, dated or obsolete inventory based on an analysis of forecasted demand compared to quantities on hand and any firm purchase orders, as well as product shelf life. To date, the Company has determined that such reserves are not required. Cost of product sales consists of third-party manufacturing costs, transportation and freight, and indirect overhead costs associated with the manufacture and distribution of INGREZZA. Cost of product sales may also include period costs related to certain inventory manufacturing services, inventory adjustment charges as well as manufacturing variances. A significant portion of the cost of producing the product sold during the three and nine month periods ended September 30, 2017 was expensed as R&D prior to our New Drug Application (NDA) approval for INGREZZA and therefore is not included in the cost of product sales during this period.

ACCOUNTS RECEIVABLE

ACCOUNTS RECEIVABLE	9 Months Ended
	Sep. 30, 2017
Text Block [Abstract]
ACCOUNTS RECEIVABLE	5. ACCOUNTS RECEIVABLE Accounts receivable are recorded net of customer allowances for prompt payment discounts, chargebacks, and any allowance for doubtful accounts. The Company estimates the allowance for doubtful accounts based on existing contractual payment terms, actual payment patterns of its customers and individual customer circumstances. To date, the Company has determined that an allowance for doubtful accounts is not required.

INVESTMENTS

INVESTMENTS	9 Months Ended
	Sep. 30, 2017
Investments Schedule [Abstract]
INVESTMENTS	6. INVESTMENTS Available-for-sale available-for-sale available-for-sale Investments consist of the following ( in thousands September 30, December 31, Certificates of deposit $ 240 $ 960 Commercial paper 66,735 49,245 Corporate debt securities 363,012 204,436 Securities of government sponsored entities 23,471 12,932 Total investments $ 453,458 $ 267,573 The following is a summary of investments classified as available-for-sale in thousands Contractual Maturity (in years) Amortized Cost Gross Unrealized Gains(1) Gross Unrealized Losses(1) Aggregate Estimated Fair Value September 30, 2017: Classified as current assets: Certificates of deposit Less than 1 $ 240 $ — $ — $ 240 Commercial paper Less than 1 66,759 — (24 ) 66,735 Corporate debt securities Less than 1 163,870 3 (131 ) 163,742 Securities of government-sponsored entities Less than 1 12,503 — (21 ) 12,482 Total short-term available-for-sale $ 243,372 $ 3 $ (176 ) $ 243,199 Classified as non-current Corporate debt securities 1 to 2 $ 199,615 $ — $ (345 ) $ 199,270 Securities of government-sponsored entities 1 to 2 11,005 — (16 ) 10,989 Total long-term available-for-sale $ 210,620 $ — $ (361 ) $ 210,259 December 31, 2016: Classified as current assets: Certificates of deposit Less than 1 $ 960 $ — $ — $ 960 Commercial paper Less than 1 49,280 3 (38 ) 49,245 Corporate debt securities Less than 1 168,548 3 (117 ) 168,434 Securities of government-sponsored entities Less than 1 5,448 — (4 ) 5,444 Total short-term available-for-sale $ 224,236 $ 6 $ (159 ) $ 224,083 Classified as non-current Corporate debt securities 1 to 2 $ 36,149 $ — $ (147 ) $ 36,002 Securities of government-sponsored entities 1 to 2 7,506 — (18 ) 7,488 Total long-term available-for-sale $ 43,655 $ — $ (165 ) $ 43,490 (1) Unrealized gains and losses are included in other comprehensive loss. The following table presents gross unrealized losses and fair value for those available-for-sale in thousands Less Than 12 Months 12 Months or Greater Total Estimated Unrealized Estimated Unrealized Estimated Unrealized September 30, 2017: Commercial paper $ 66,735 $ (24 ) $ — $ — $ 66,735 $ (24 ) Corporate debt securities 325,223 (463 ) 14,298 (13 ) 339,521 (476 ) Securities of government-sponsored entities 15,988 (17 ) 7,483 (20 ) 23,471 (37 ) Total $ 407,946 $ (504 ) $ 21,781 $ (33 ) $ 429,727 $ (537 ) December 31, 2016: Commercial paper $ 43,781 $ (38 ) $ — $ — $ 43,781 $ (38 ) Corporate debt securities 185,243 (261 ) 9,144 (3 ) 194,387 (264 ) Securities of government-sponsored entities 12,932 (22 ) — — 12,932 (22 ) Total $ 241,956 $ (321 ) $ 9,144 $ (3 ) $ 251,100 $ (324 ) The primary objective of the Company’s investment portfolio is to enhance overall returns in an efficient manner while maintaining safety of principal, prudent levels of liquidity and acceptable levels of risk. The Company’s investment policy limits interest-bearing security investments to certain types of instruments issued by institutions with primarily investment grade credit ratings and places restrictions on maturities and concentration by asset class and issuer. The Company reviews the available-for-sale available-for-sale

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	7. FAIR VALUE MEASUREMENTS Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, a three-tier fair value hierarchy has been established, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets; Level 2: Inputs include quoted prices for similar instruments in active markets and/or quoted prices for identical or similar instruments in markets that are not active near the measurement date; and Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. The Company classifies its cash equivalents and available-for-sale two-sided The Company’s assets which were measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016 were determined using the inputs described above and are as follows ( in millions Fair Value Measurements Using Carrying Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) September 30, 2017: Classified as current assets: Cash and money market funds $ 269.4 $ 269.4 $ — $ — Certificates of deposit 0.2 0.2 — — Commercial paper 66.7 — 66.7 — Securities of government-sponsored entities 12.5 — 12.5 — Corporate debt securities 163.7 — 163.7 — Subtotal 512.5 269.6 242.9 — Classified as long-term assets: Certificates of deposit 3.0 3.0 — — Securities of government-sponsored entities 11.0 — 11.0 — Corporate debt securities 199.3 — 199.3 — Total 725.8 272.6 453.2 — Less cash, cash equivalents and restricted cash (272.4 ) (272.4 ) — — Total investments $ 453.4 $ 0.2 $ 453.2 $ — December 31, 2016: Classified as current assets: Cash and money market funds $ 73.6 $ 73.6 $ — $ — Certificates of deposit 1.0 1.0 — — Commercial paper 49.2 — 49.2 — Securities of government-sponsored entities 5.4 — 5.4 — Corporate debt securities 178.1 — 178.1 — Subtotal 307.3 74.6 232.7 — Classified as long-term assets: Certificates of deposit 4.9 4.9 — — Securities of government-sponsored entities 7.5 — 7.5 — Corporate debt securities 36.0 — 36.0 — Total 355.7 79.5 276.2 — Less cash, cash equivalents and restricted cash (88.1 ) (78.5 ) (9.6 ) — Total investments $ 267.6 $ 1.0 $ 266.6 $ — The carrying amounts of the Company’s receivables and payables approximate their fair value due to their short maturities.

SHARE-BASED COMPENSATION

SHARE-BASED COMPENSATION	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
SHARE-BASED COMPENSATION	8. SHARE-BASED COMPENSATION The compensation expense related to the Company’s share-based compensation arrangements has been included in the condensed consolidated statements of comprehensive loss as follows ( in millions Three Months Ended Nine Months Ended 2017 2016 2017 2016 Sales, general and administrative $ 6.5 $ 3.5 $ 18.2 $ 11.8 Research and development 3.7 2.8 $ 10.9 $ 8.7 Total share-based compensation expense $ 10.2 $ 6.3 $ 29.1 $ 20.5 The fair value of equity instruments that vest based on continued employee service, net of estimated forfeitures, is recognized and amortized on a straight-line basis over the requisite service period. For restricted stock units (RSUs) with performance-based vesting requirements (PRSUs), no expense is recorded until the performance condition is probable of being achieved. The Company estimates forfeiture rates for equity awards based on past behavior for similar equity awards with further consideration given to the class of employees to whom the equity awards were granted. As of September 30, 2017, total unrecognized estimated compensation cost related to non-vested non-vested During the nine months ended September 30, 2017 and 2016, stock options to purchase approximately 1.0 million and 0.3 million shares of the Company’s common stock were exercised, respectively. The cash received by the Company from stock option exercises during the nine months ended September 30, 2017 and 2016 was approximately $8.3 million and $2.3 million, respectively. The Company also issued approximately 0.3 million shares of common stock pursuant to the vesting of RSUs during each of the nine months ended September 30, 2017 and 2016, and 0.2 million shares of common stock pursuant to the vesting of PRSUs during the second quarter of 2017. Stock Option Assumptions The Company granted stock options to purchase approximately 1.6 million and 1.0 million shares of the Company’s common stock during the nine months ended September 30, 2017 and 2016, respectively. These stock options generally vest monthly over a four-year period. The exercise price of all stock options granted during the nine months ended September 30, 2017 and 2016 was equal to the closing price of the Company’s common stock on the date of grant. The estimated fair value of each stock option granted was determined on the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions for the stock option grants: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Risk-free interest rate 1.8 % 1.1 % 2.0 % 1.4 % Expected volatility of common stock 59.6 % 59.3 % 58.2 % 60.0 % Dividend yield 0.0 % 0.0 % 0.0 % 0.0 % Expected option term 5 years 5 years 5.7 years 5.6 years The Black-Scholes option-pricing model incorporates various and highly sensitive assumptions including expected volatility, expected term and interest rates. The expected volatility is based on the historical volatility of the Company’s common stock over the most recent period commensurate with the estimated expected term of the Company’s stock options. The expected option term is estimated based on historical experience as well as the status of the employee. For example, directors and officers have a longer expected option term than all other employees. The risk-free rate for periods within the contractual life of the option is based upon observed interest rates appropriate for the expected term of the Company’s employee stock options. The Company has never declared or paid dividends and has no plans to do so in the foreseeable future. For the nine months ended September 30, 2017 and 2016, share-based compensation expense related to stock options was $18.7 million and $13.1 million, respectively. Restricted Stock Units During the nine months ended September 30, 2017 and 2016, the Company granted approximately 0.6 million and 0.3 million RSUs, respectively, that generally vest annually over a four-year period. Additionally, during the nine months ended September 30, 2016, the Company granted approximately 0.2 million PRSUs. These PRSUs vest based on the achievement of pre-defined

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
STOCKHOLDERS' EQUITY	9. STOCKHOLDERS’ EQUITY Equity Financing In February 2017, the Company filed an automatic shelf registration statement which immediately became effective by rule of the SEC. For so long as the Company continues to satisfy the requirements to be deemed a well-known seasoned issuer, this shelf registration statement allows the Company to issue an unlimited number of securities from time to time. As of September 30, 2017, the Company had not sold any securities under this shelf registration statement. The specific terms of future offerings, if any, under the shelf registration statement would be established at the time of such offerings.

REAL ESTATE

REAL ESTATE	9 Months Ended
	Sep. 30, 2017
Leases [Abstract]
REAL ESTATE	10. REAL ESTATE In December 2007, the Company closed the sale of its facility and associated real property for a purchase price of $109 million. Concurrent with the sale, the Company retired the entire $47.7 million in mortgage debt previously outstanding with respect to the facility and associated real property, and received cash of $61.0 million net of transaction costs and debt retirement. Upon the closing of the sale of the facility and associated real property, the Company entered into a lease agreement (Lease) whereby it leased back for an initial term of 12 years its corporate headquarters comprised of two buildings located at 12790 El Camino Real (Front Building) and 12780 El Camino Real (Rear Building) in San Diego, California. The Company also entered into a series of lease amendments (Amendments), beginning in late 2008 through 2011, through which it was able to vacate the Front Building, but continue to occupy the Rear Building. The ultimate result of this real estate sale was a net gain of $39.1 million which was deferred in accordance with authoritative guidance. The Company recognized $0.2 million and $0.9 million of the deferred gain during the three month periods ending September 30, 2017 and 2016, respectively. The Company recognized $2.0 million and $2.6 million of the deferred gain during the nine month periods ending September 30, 2017 and 2016, respectively, and will recognize the remaining $9.0 million of the deferred gain on a straight-line basis over the amended Lease term which will expire at the end of 2029. During 2017, the Company entered into an amendment to extend the current term of the Lease through December 31, 2029 (Term Amendment). Under the Term Amendment, the Company reduced its base rental rate by approximately 8% and will continue to pay base annual rent (subject to an annual fixed percentage increase), plus a 3.5% annual management fee, property taxes and other normal and necessary expenses associated with the Lease such as utilities, repairs and maintenance. Certain incentives were included in the Term Amendment, including approximately $13.1 million in various tenant improvement allowances, three months of rent abatement, and a reduction in the required security deposit amount from $4.7 million to $3.0 million. In lieu of a cash security deposit, Wells Fargo Bank, N.A. issued on the Company’s behalf a letter of credit in the amount of $3.0 million, which is secured by a deposit of equal amount with the same bank. The Company also has the right to extend the Lease for two consecutive ten-year As of September 30, 2017, the Company had one sublease agreement for approximately 16,000 square feet of the Rear Building. This sublease is expected to result in approximately $0.6 million of rental income in 2017 with this sublease rental income being recorded as an offset to rent expense. The income generated under this sublease is lower than the Company’s financial obligation under the Lease for the Rear Building, as determined on a per square foot basis. Consequently, at the inception of a sublease, or in association with an amendment to a sublease, the Company is required to record a cease-use The following table sets forth changes to the accrued cease-use in thousands Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Beginning balance $ 181 $ 972 $ 853 $ 1,983 Change in estimate — — (544 ) (830 ) Payments (60 ) (58 ) (188 ) (239 ) Ending balance $ 121 $ 914 $ 121 $ 914

CONVERTIBLE SENIOR NOTES

CONVERTIBLE SENIOR NOTES	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
CONVERTIBLE SENIOR NOTES	11. CONVERTIBLE SENIOR NOTES On May 2, 2017, the Company completed a private placement of $517.5 million in aggregate principal amount of 2.25% convertible senior notes due 2024 (2024 Notes) and entered into an indenture agreement (2024 Indenture) with respect to the 2024 Notes. The 2024 Notes accrue interest at a fixed rate of 2.25% per year, payable semiannually in arrears on May 15 and November 15 of each year, beginning on November 15, 2017. The 2024 Notes mature on May 15, 2024. The net proceeds from the issuance of the 2024 Notes were approximately $502.8 million, after deducting commissions and the offering expenses payable by the Company. Holders of the 2024 Notes may convert the 2024 Notes at any time prior to the close of business on the business day immediately preceding May 15, 2024, only under the following circumstances: (i) during any calendar quarter commencing after the calendar quarter ending on September 30, 2017 (and only during such calendar quarter), if the last reported sale price of the Company’s common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than 130% of the conversion price on each applicable trading day; (ii) during the five business-day trading-day (iii) upon the occurrence of specified corporate events, including a merger or a sale of all or substantially all of the Company’s assets; or (iv) if the Company calls the 2024 Notes for redemption, until the close of business on the business day immediately preceding the redemption date. On or after January 15, 2024, until the close of business on the scheduled trading day immediately preceding May 15, 2024, holders may convert their 2024 Notes at any time. Upon conversion, holders will receive the principal amount of their 2024 Notes and any excess conversion value, calculated based on the per share volume-weighted average price for each of the 30 consecutive trading days during the observation period (as more fully described in the 2024 Indenture). For both the principal and excess conversion value, holders may receive 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 option. It is the Company’s intent and policy to settle conversions through combination settlement, which essentially involves repayment of an amount of cash equal to the “principal portion” and delivery of the “share amount” in excess of the principal portion in shares of common stock or cash. In general, for each $1,000 in principal, the “principal portion” of cash upon settlement is defined as the lesser of $1,000, and the conversion value during the 25-day The initial conversion rate for the 2024 Notes is 13.1711 shares of common stock per $1,000 principal amount, which is equivalent to an initial conversion price of approximately $75.92 per share of the Company’s common stock. The conversion rate will be subject to adjustment in some events but will not be adjusted for any accrued and unpaid interest. The initial conversion price of the 2024 Notes represents a premium of approximately 42.5% to the closing sale price of $53.28 per share of the Company’s common stock on the NASDAQ Global Select Market on April 26, 2017, the date that the Company priced the private offering of the 2024 Notes. In the event of conversion, holders would forgo all future interest payments, any unpaid accrued interest and the possibility of further stock price appreciation. Upon the receipt of conversion requests, the settlement of the 2024 Notes will be paid pursuant to the terms of the 2024 Indenture. In the event that all of the 2024 Notes are converted, the Company would be required to repay the $517.5 million in principal value and any conversion premium in any combination of cash and shares of its common stock (at the Company’s option). Prior to May 15, 2021, the Company may not redeem the 2024 Notes. On or after May 15, 2021, the Company may redeem for cash all or part of the 2024 Notes if the last reported sale price (as defined in the 2024 Indenture) of the Company’s common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading-day If the Company undergoes a fundamental change, as defined in the 2024 Indenture, subject to certain conditions, holders of the 2024 Notes may require the Company to repurchase for cash all or part of their 2024 Notes at a repurchase price equal to 100% of the principal amount of the 2024 Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date. In addition, if a ‘‘make-whole fundamental change’’ (as defined in the 2024 Indenture) occurs prior to January 15, 2024, the Company will, in certain circumstances, increase the conversion rate for a holder who elects to convert its notes in connection with the make-whole fundamental change. The 2024 Notes are the Company’s general unsecured obligations that rank senior in right of payment to all of its indebtedness that is expressly subordinated in right of payment to the 2024 Notes, and equal in right of payment to the Company’s unsecured indebtedness. The fair value of the 2024 Notes is estimated utilizing market quotations from an over-the-counter While the 2024 Notes are currently classified on the Company’s consolidated balance sheet at September 30, 2017 as long-term, the future convertibility and resulting balance sheet classification of this liability will be monitored at each quarterly reporting date and will be analyzed dependent upon market prices of the Company’s common stock during the prescribed measurement periods. In the event that the holders of the 2024 Notes have the election to convert the 2024 Notes at any time during the prescribed measurement period, the 2024 Notes would then be considered a current obligation and classified as such. Under current accounting guidance, an entity must separately account for the liability and equity components of convertible debt instruments (such as the 2024 Notes) that may be settled entirely or partially in cash upon conversion in a manner that reflects the issuer’s economic interest cost. The liability component of the instrument was valued in a manner that reflects the market interest rate for a similar nonconvertible instrument at the date of issuance. The initial carrying value of the liability component of $368.3 million was calculated using a 7.5% assumed borrowing rate. The equity component of $149.2 million, representing the conversion option, was determined by deducting the fair value of the liability component from the par value of the 2024 Notes and is recorded in additional paid-in re-measured The Company allocated the total transaction costs of approximately $14.7 million related to the issuance of the 2024 Notes to the liability and equity components of the 2024 Notes based on their relative values. Transaction costs attributable to the liability component are amortized to interest expense over the seven-year term of the 2024 Notes, and transaction costs attributable to the equity component are netted with the equity component in stockholders’ equity. The 2024 Notes do not contain any financial or operating covenants or any restrictions on the payment of dividends, the issuance of other indebtedness or the issuance or repurchase of securities by the Company. The 2024 Indenture contains customary events of default with respect to the 2024 Notes, including that upon certain events of default, 100% of the principal and accrued and unpaid interest on the 2024 Notes will automatically become due and payable. Debt, net of discounts and deferred financing costs at September 30, 2017, consisted of the following: Principal $ 517,500 Deferred financing costs (9,975 ) Debt discount, net (142,415 ) Net carrying amount $ 365,110

LOSS PER COMMON SHARE

LOSS PER COMMON SHARE	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
LOSS PER COMMON SHARE	12. LOSS PER COMMON SHARE The Company computes basic net loss per share using the weighted average number of common shares outstanding during the period. In computing the diluted net loss, potentially dilutive securities, composed of incremental common shares issuable upon the exercise of stock options and warrants and the vesting of RSUs and PRSUs as well as the conversion of the excess conversion value on the 2024 Notes, are excluded from the diluted loss per share calculation because of their anti-dilutive effect. Since it is the Company’s intent to settle the principal amount of its convertible senior notes in cash, the potentially dilutive effect of such notes on net income (loss) per share is computed under the treasury stock method. Basic net income (loss) per share is calculated by dividing the net income (loss) attributable to common shares by the weighted average number of common shares outstanding during the period. Diluted net income (loss) per common share is calculated by dividing the net income (loss) attributable to common shares by the weighted average number of common shares outstanding plus dilutive potential common stock outstanding during the period. Potential common shares outstanding include the shares of common stock issuable upon the exercise of outstanding stock options and the vesting of RSUs, calculated using the treasury stock method. In addition, since it is the Company’s intent to settle the principal amount of its 2024 Notes in cash, the potentially dilutive effect of these notes is also calculated under the treasury stock method. Potential common shares are excluded from the diluted net loss per share computation to the extent they would be antidilutive. Because the Company reported a net loss for the three and nine months ended September 30, 2017 and 2016, no potentially dilutive securities have been included in the computation of diluted net loss per share for those periods. For the three and nine months ended September 30, 2017, the Company realized a net loss of $11.1 million and $149.4 million, respectively. Options to purchase approximately 0.2 million and 0.4 million shares of common stock were outstanding during the three and nine months ended September 30, 2017, respectively, with an exercise price greater than the average market price of the underlying common shares. For the three and nine months ended September 30, 2016, the Company realized a net loss of $36.9 million and $96.4 million, respectively. Options to purchase approximately 0.1 million and 0.4 million shares of common stock were outstanding during each of the three and nine months ended September 30, 2016, with an exercise price greater than the average market price of the underlying common shares.

RESEARCH AND DEVELOPMENT

RESEARCH AND DEVELOPMENT	9 Months Ended
	Sep. 30, 2017
Research and Development [Abstract]
RESEARCH AND DEVELOPMENT	13. RESEARCH AND DEVELOPMENT R&D expenses consist primarily of salaries, payroll taxes, employee benefits, and share-based compensation charges, for those individuals involved in ongoing R&D efforts; as well as scientific contractor fees, preclinical and clinical trial costs, R&D facilities costs, laboratory supply costs, and depreciation of scientific equipment. All such costs are charged to R&D expense as incurred. These expenses result from the Company’s independent R&D efforts as well as efforts associated with collaborations and in-licensing

BIAL AGREEMENT

BIAL AGREEMENT	9 Months Ended
	Sep. 30, 2017
Text Block [Abstract]
BIAL AGREEMENT	14. BIAL AGREEMENT In February 2017, the Company entered into an exclusive license agreement with BIAL– Portela & CA, S.A. (BIAL) for the development and commercialization of opicapone for the treatment of human diseases and conditions, including Parkinson’s disease, in the United States and Canada. Under the terms of the agreement, the Company is responsible for the management and cost of all opicapone development and commercialization activities in the United States and Canada. Under the terms of the agreement, the Company paid BIAL an upfront license fee of $30 million, and may also be required to pay up to an additional $115 million in milestone payments associated with the regulatory approval and net sales of products containing opicapone. The initial upfront license fee was expensed in the first quarter of 2017 as in-process The agreement, unless terminated earlier, will continue on a licensed product-by-licensed country-by-country

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	15. COMMITMENTS AND CONTINGENCIES On December 1, 2015, Icahn School of Medicine at Mount Sinai (Mount Sinai) filed a complaint against the Company in the United States District Court for the Southern District of New York: Icahn School of Medicine at Mount Sinai v. Neurocrine Biosciences, Inc., Case No. 1:15-cv-09414. The Company is not aware of any other proceedings or claims that it believes will have, individually or in the aggregate, a material adverse effect on its business, financial condition or results of operations.

CONCENTRATION RISK

CONCENTRATION RISK	9 Months Ended
	Sep. 30, 2017
Risks and Uncertainties [Abstract]
CONCENTRATION RISK	16. CONCENTRATION RISK The Company does not currently have any of its own manufacturing facilities, and therefore it depends on an outsourced manufacturing strategy for the production of INGREZZA for commercial use and for the production of its product candidates for clinical trials. The Company has contracts in place with one third-party manufacturer that is approved for the commercial production of INGREZZA’s capsules and one third-party manufacturer that is approved for the production of INGREZZA’s active pharmaceutical ingredient. Although there are potential sources of supply other than the Company’s existing suppliers, any new supplier would be required to qualify under applicable regulatory requirements. The Company has entered into distribution agreements with a limited number of SPs and SDs, and all of the Company’s product sales are to these customers. The Company’s three largest customers represented all of the Company’s product revenue for the quarter ended September 30, 2017 and all of the Company’s accounts receivable balance at September 30, 2017.

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	9 Months Ended
	Sep. 30, 2017
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	17. SUBSEQUENT EVENTS During October 2017, the Company was notified by AbbVie that the NDA submission for elagolix was accepted as filed by the FDA. This filing generated a $30 million event-based payment to the Company during the fourth quarter of 2017, which is payable by AbbVie within 30 days of the event.

ORGANIZATION AND SIGNIFICANT 23

ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Description of Business	Description of Business. ® catechol-O-methyltransferase
Basis of Presentation	Basis of Presentation 10-Q 10-01 S-X. These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2016 included in the Company’s Annual Report on Form 10-K
Impact of Recently Issued Accounting Standards	Impact of Recently Issued Accounting Standards The Company does not anticipate the new standard having a material impact on currently reported net product sales. The Company is also currently evaluating the impact of the new standard on historical revenue recorded for its two collaboration agreements. This ongoing evaluation is dependent upon the resolution of certain questions relating to the application of, and transition to, the new revenue recognition guidance for collaboration agreements which will ultimately determine the adoption method and the ultimate impact the adoption of this standard will have on the Company’s consolidated financial statements. Based on the Company’s current assessment of the effect of the new standard on historical revenue under its collaboration agreements that is related to contingent payments, which are not dependent on its performance, the Company believes revenue could potentially be recognized earlier than historically recorded if information is available to allow the Company to record the payments without the risk of a future reversal. In February 2016, the FASB issued Accounting Standards Update (ASU) 2016-02 In November 2016, the FASB issued ASU 2016-18, beginning-of-period end-of-period beginning-of-period end-of-period
Use of Estimates	Use of Estimates
Revenue Recognition Policy	Revenue Recognition Policy. INGREZZA was approved by the FDA on April 11, 2017 and the Company commenced shipments of INGREZZA to select pharmacies (SPs) and a select distributor (SD) in late April 2017. The SPs dispense product to a patient based on the fulfillment of a prescription and the SD sells product to government facilities, long-term care pharmacies or in-patient The Company has determined it can reasonably estimate its allowances for rebates and chargebacks at the time title and risk of loss transfers to the SP or SD. Therefore, the Company records revenue when the product is delivered to the SPs or SD, which is an approach frequently referred to as the “sell-in” The Company recognizes revenue from product sales net of the following allowances: Distribution Fees: Rebates: Chargebacks: Co-Payment co-payment Co-payment Product Returns:
Revenue Recognition Policy	Revenue Recognition Policy. Since 2011, the Company has followed the Accounting Standards Codification (ASC) for Revenue Recognition—Multiple-Element Arrangements, if applicable, to determine the recognition of revenue under license and collaboration agreements. The terms of these agreements generally contain multiple elements, or deliverables, which may include (i) licenses to the Company’s intellectual property, (ii) materials and technology, (iii) pharmaceutical supply, (iv) participation on joint development or joint steering committees, and (v) development services. The payments the Company receives under these arrangements typically include one or more of the following: up-front The ASC provides guidance relating to the separation of deliverables included in an arrangement into different units of accounting and the allocation of consideration to the units of accounting. The evaluation of multiple-element arrangements requires management to make judgments about (i) the identification of deliverables, (ii) whether such deliverables are separable from the other aspects of the contractual relationship, (iii) the estimated selling price of each deliverable, and (iv) the expected period of performance for each deliverable. To determine the units of accounting under a multiple-element arrangement, management evaluates certain separation criteria, including whether the deliverables have stand-alone value, based on the relevant facts and circumstances for each arrangement. The selling prices of deliverables under an arrangement may be derived using vendor specific objective evidence (VSOE), third-party evidence, or a best estimate of selling price (BESP), if VSOE or third-party evidence is not available. For most pharmaceutical licensing and collaboration agreements, BESP is utilized. The objective of BESP is to determine the price at which the Company would transact a sale if the element within the agreement was sold on a standalone basis. Establishing BESP involves management’s judgment and considers multiple factors, including market conditions and company-specific factors, including those factors contemplated in negotiating the agreements, as well as internally developed models that include assumptions related to market opportunity, discounted cash flows, estimated development costs, probability of success and the time needed to commercialize a product candidate pursuant to the agreement. In validating the BESP, management considers whether changes in key assumptions used to determine the BESP will have a significant effect on the allocation of the arrangement consideration between the multiple deliverables. The allocated consideration for each unit of accounting is recognized over the related obligation period in accordance with the applicable revenue recognition criteria. If there are deliverables in an arrangement that are not separable from other aspects of the contractual relationship, they are treated as a combined unit of accounting, with the allocated revenue for the combined unit recognized in a manner consistent with the revenue recognition applicable to the final deliverable in the combined unit. Payments received prior to satisfying the relevant revenue recognition criteria are recorded as unearned revenue in the accompanying balance sheets and recognized as revenue when the related revenue recognition criteria are met. The Company typically receives up-front For payments payable on achievement of milestones that do not meet all of the conditions to be considered substantive, the Company recognizes the portion of the payment allocable to delivered items as revenue when the specific milestone is achieved, and the contingency is removed. Prior to the revised multiple element guidance described above, adopted by the Company on January 1, 2011, upfront, nonrefundable payments for license fees, grants, and advance payments for sponsored research revenues received in excess of amounts earned were classified as deferred revenue and recognized as income over the contract or development period. Revenues from development milestones are accounted for in accordance with the Revenue Recognition – Milestone Method Topic of the FASB ASC (Milestone Method). Milestones are recognized when earned, as evidenced by written acknowledgment from the collaborator or other persuasive evidence that the milestone has been achieved, provided that the milestone event is substantive. A milestone event is considered to be substantive if its achievability was not reasonably assured at the inception of the agreement and the Company’s efforts led to the achievement of the milestone or the milestone was due upon the occurrence of a specific outcome resulting from the Company’s performance. The Company assesses whether a milestone is substantive at the inception of each agreement. Mitsubishi Tanabe Pharma Corporation (Mitsubishi Tanabe). (NBI-98854) up-front Under the terms of the Company’s agreement with Mitsubishi Tanabe, the collaboration effort between the parties to advance valbenazine towards commercialization in Japan and other select Asian markets is governed by a joint steering committee and joint development committee with representatives from both the Company and Mitsubishi Tanabe. There are no performance, cancellation, termination or refund provisions in the agreement that would have a material financial consequence to the Company. The Company does not directly control when event-based payments will be achieved or when royalty payments will begin. Mitsubishi Tanabe may terminate the agreement at its discretion upon 180 days’ written notice to the Company. In such event, all valbenazine product rights for Japan and other select Asian markets would revert to the Company. The Company has identified the following deliverables associated with the Mitsubishi Tanabe agreement: valbenazine technology license and existing know-how, As discussed above, the BESP method required the use of significant estimates. The Company used an income approach to estimate the selling price for the technology license and an expense approach for estimating development activities and the manufacture of pharmaceutical products. The development activities and the manufacture of pharmaceutical products are expected to be delivered throughout the duration of the agreement. The technology license and existing know-how During the first quarter of 2015, the Company recognized revenue under this agreement of $19.8 million associated with the delivery of a technology license and existing know-how. million up-front up-front non-contingent The Company evaluated the event-based payments under the Milestone Method and concluded only one immaterial event-based payment represents a substantive milestone. Event-based payments will be recognized when earned. During the third quarter of 2017, the Company recognized $15 million in development event-based payments resulting from Mitsubishi Tanabe’s initiation of Phase II/III development of valbenazine in tardive dyskinesia in Asia. The Company is eligible to receive from Mitsubishi Tanabe tiered royalty payments based on product sales in Japan and other select Asian markets. Royalties will be recognized as earned in accordance with the terms of the agreement, when product sales are reported by Mitsubishi Tanabe, the amount can be reasonably estimated, and collectability is reasonably assured. AbbVie Inc. (AbbVie) . Under the terms of the agreement, AbbVie is responsible for all third-party development, marketing and commercialization costs. The Company will be entitled to a percentage of worldwide sales of GnRH Compounds for the longer of ten years or the life of the related patent rights. AbbVie may terminate the collaboration at its discretion upon 180 days’ written notice to the Company. In such event, the Company would be entitled to specified payments for ongoing clinical development and related activities and all GnRH Compound product rights would revert to the Company. During the first quarter of 2016, the Company recognized $15 million in development event-based payments resulting from AbbVie initiating Phase III development of elagolix in uterine fibroids.

INVESTMENTS (Tables)

INVESTMENTS (Tables)	9 Months Ended
	Sep. 30, 2017
Investments Schedule [Abstract]
Investments	Investments consist of the following ( in thousands September 30, December 31, Certificates of deposit $ 240 $ 960 Commercial paper 66,735 49,245 Corporate debt securities 363,012 204,436 Securities of government sponsored entities 23,471 12,932 Total investments $ 453,458 $ 267,573
Summary of Investments Classified as Available-For-Sale Securities	The following is a summary of investments classified as available-for-sale in thousands Contractual Maturity (in years) Amortized Cost Gross Unrealized Gains(1) Gross Unrealized Losses(1) Aggregate Estimated Fair Value September 30, 2017: Classified as current assets: Certificates of deposit Less than 1 $ 240 $ — $ — $ 240 Commercial paper Less than 1 66,759 — (24 ) 66,735 Corporate debt securities Less than 1 163,870 3 (131 ) 163,742 Securities of government-sponsored entities Less than 1 12,503 — (21 ) 12,482 Total short-term available-for-sale $ 243,372 $ 3 $ (176 ) $ 243,199 Classified as non-current Corporate debt securities 1 to 2 $ 199,615 $ — $ (345 ) $ 199,270 Securities of government-sponsored entities 1 to 2 11,005 — (16 ) 10,989 Total long-term available-for-sale $ 210,620 $ — $ (361 ) $ 210,259 December 31, 2016: Classified as current assets: Certificates of deposit Less than 1 $ 960 $ — $ — $ 960 Commercial paper Less than 1 49,280 3 (38 ) 49,245 Corporate debt securities Less than 1 168,548 3 (117 ) 168,434 Securities of government-sponsored entities Less than 1 5,448 — (4 ) 5,444 Total short-term available-for-sale $ 224,236 $ 6 $ (159 ) $ 224,083 Classified as non-current Corporate debt securities 1 to 2 $ 36,149 $ — $ (147 ) $ 36,002 Securities of government-sponsored entities 1 to 2 7,506 — (18 ) 7,488 Total long-term available-for-sale $ 43,655 $ — $ (165 ) $ 43,490 (1) Unrealized gains and losses are included in other comprehensive loss.
Gross Unrealized Losses and Fair Value Available-For-Sale Investments in Unrealized Loss Position	The following table presents gross unrealized losses and fair value for those available-for-sale in thousands Less Than 12 Months 12 Months or Greater Total Estimated Unrealized Estimated Unrealized Estimated Unrealized September 30, 2017: Commercial paper $ 66,735 $ (24 ) $ — $ — $ 66,735 $ (24 ) Corporate debt securities 325,223 (463 ) 14,298 (13 ) 339,521 (476 ) Securities of government-sponsored entities 15,988 (17 ) 7,483 (20 ) 23,471 (37 ) Total $ 407,946 $ (504 ) $ 21,781 $ (33 ) $ 429,727 $ (537 ) December 31, 2016: Commercial paper $ 43,781 $ (38 ) $ — $ — $ 43,781 $ (38 ) Corporate debt securities 185,243 (261 ) 9,144 (3 ) 194,387 (264 ) Securities of government-sponsored entities 12,932 (22 ) — — 12,932 (22 ) Total $ 241,956 $ (321 ) $ 9,144 $ (3 ) $ 251,100 $ (324 )

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Assets Measured at Fair Value on Recurring Basis	The Company’s assets which were measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016 were determined using the inputs described above and are as follows ( in millions Fair Value Measurements Using Carrying Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) September 30, 2017: Classified as current assets: Cash and money market funds $ 269.4 $ 269.4 $ — $ — Certificates of deposit 0.2 0.2 — — Commercial paper 66.7 — 66.7 — Securities of government-sponsored entities 12.5 — 12.5 — Corporate debt securities 163.7 — 163.7 — Subtotal 512.5 269.6 242.9 — Classified as long-term assets: Certificates of deposit 3.0 3.0 — — Securities of government-sponsored entities 11.0 — 11.0 — Corporate debt securities 199.3 — 199.3 — Total 725.8 272.6 453.2 — Less cash, cash equivalents and restricted cash (272.4 ) (272.4 ) — — Total investments $ 453.4 $ 0.2 $ 453.2 $ — December 31, 2016: Classified as current assets: Cash and money market funds $ 73.6 $ 73.6 $ — $ — Certificates of deposit 1.0 1.0 — — Commercial paper 49.2 — 49.2 — Securities of government-sponsored entities 5.4 — 5.4 — Corporate debt securities 178.1 — 178.1 — Subtotal 307.3 74.6 232.7 — Classified as long-term assets: Certificates of deposit 4.9 4.9 — — Securities of government-sponsored entities 7.5 — 7.5 — Corporate debt securities 36.0 — 36.0 — Total 355.7 79.5 276.2 — Less cash, cash equivalents and restricted cash (88.1 ) (78.5 ) (9.6 ) — Total investments $ 267.6 $ 1.0 $ 266.6 $ —

SHARE-BASED COMPENSATION (Table

SHARE-BASED COMPENSATION (Tables)	9 Months Ended
	Sep. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Compensation Expenses Related to Share Based Compensation	The compensation expense related to the Company’s share-based compensation arrangements has been included in the condensed consolidated statements of comprehensive loss as follows ( in millions Three Months Ended Nine Months Ended 2017 2016 2017 2016 Sales, general and administrative $ 6.5 $ 3.5 $ 18.2 $ 11.8 Research and development 3.7 2.8 $ 10.9 $ 8.7 Total share-based compensation expense $ 10.2 $ 6.3 $ 29.1 $ 20.5
Weighted-Average Assumptions for Stock Option Grants using Black-Scholes Option-Pricing Model	The estimated fair value of each stock option granted was determined on the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions for the stock option grants: Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Risk-free interest rate 1.8 % 1.1 % 2.0 % 1.4 % Expected volatility of common stock 59.6 % 59.3 % 58.2 % 60.0 % Dividend yield 0.0 % 0.0 % 0.0 % 0.0 % Expected option term 5 years 5 years 5.7 years 5.6 years

REAL ESTATE (Tables)

REAL ESTATE (Tables)	9 Months Ended
	Sep. 30, 2017
Leases [Abstract]
Changes to Accrued Cease-Use Liability	The following table sets forth changes to the accrued cease-use in thousands Three Months Ended September 30, Nine Months Ended September 30, 2017 2016 2017 2016 Beginning balance $ 181 $ 972 $ 853 $ 1,983 Change in estimate — — (544 ) (830 ) Payments (60 ) (58 ) (188 ) (239 ) Ending balance $ 121 $ 914 $ 121 $ 914

CONVERTIBLE SENIOR NOTES (Table

CONVERTIBLE SENIOR NOTES (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Debt Net of Discount and Deferred Financing Costs	Debt, net of discounts and deferred financing costs at September 30, 2017, consisted of the following: Principal $ 517,500 Deferred financing costs (9,975 ) Debt discount, net (142,415 ) Net carrying amount $ 365,110

Revenue Recognition and Signifi

Revenue Recognition and Significant Collaborative Research and Development Agreements - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended			9 Months Ended	12 Months Ended
	Jun. 30, 2010	Sep. 30, 2017	Mar. 31, 2016	Mar. 31, 2015	Sep. 30, 2017	Dec. 31, 2015
Mitsubishi Tanabe
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Up-front license fees						$ 30,000,000
Collaborative agreement maximum additional payment to receive						85,000,000
Patent rights period					The longer of ten years or the life of the related patent rights.
Clinical trial cost						$ 12,000,000
Collaborative arrangement right description					Under the terms of the Company’s agreement with Mitsubishi Tanabe, the collaboration effort between the parties to advance valbenazine towards commercialization in Japan and other select Asian markets is governed by a joint steering committee and joint development committee with representatives from both the Company and Mitsubishi Tanabe. There are no performance, cancellation, termination or refund provisions in the agreement that would have a material financial consequence to the Company. The Company does not directly control when event-based payments will be achieved or when royalty payments will begin. Mitsubishi Tanabe may terminate the agreement at its discretion upon 180 days’ written notice to the Company. In such event, all valbenazine product rights for Japan and other select Asian markets would revert to the Company.
Collaboration termination notice period					180 days
Revenues recognized under collaboration agreement		$ 15,000,000		$ 19,800,000
Deferred revenues under collaboration				$ 10,200,000
AbbVie
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Patent rights period					Ten years or the life of the related patent rights.
Collaborative arrangement right description					The Company will be entitled to a percentage of worldwide sales of GnRH Compounds for the longer of ten years or the life of the related patent rights.
Collaboration termination notice period					180 days
Revenues recognized under collaboration agreement			$ 15,000,000
AbbVie
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Up-front license fees	$ 75,000,000
Amount remains outstanding under collaboration agreement		485,000,000			$ 485,000,000
AbbVie | Development and Regulatory Milestone Payments
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative agreement maximum additional payment to receive		480,000,000			480,000,000
Collaborative agreement payment received					45,000,000
AbbVie | Commercial Milestone Payments
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative agreement maximum additional payment to receive		$ 50,000,000			$ 50,000,000

Investments (Detail)

Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of Investments [Line Items]
Investments	$ 453,458	$ 267,573
Certificates of deposit
Schedule of Investments [Line Items]
Investments	240	960
Commercial paper
Schedule of Investments [Line Items]
Investments	66,735	49,245
Corporate debt securities
Schedule of Investments [Line Items]
Investments	363,012	204,436
Domestic and foreign government agencies debt securities
Schedule of Investments [Line Items]
Investments	$ 23,471	$ 12,932

Summary of Investments Classifi

Summary of Investments Classified as Available-For-Sale Securities (Detail) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Aggregate Estimated Fair Value		$ 453,458	$ 267,573
Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Aggregate Estimated Fair Value		240	960
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Aggregate Estimated Fair Value		66,735	49,245
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Aggregate Estimated Fair Value		363,012	204,436
Domestic and foreign government agencies debt securities
Schedule of Available-for-sale Securities [Line Items]
Aggregate Estimated Fair Value		23,471	12,932
Short-term investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		243,372	224,236
Gross Unrealized Gains	[1]	3	6
Gross Unrealized Losses	[1]	(176)	(159)
Aggregate Estimated Fair Value		243,199	224,083
Short-term investments | Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		240	960
Gross Unrealized Gains	[1]	0	0
Gross Unrealized Losses	[1]	0	0
Aggregate Estimated Fair Value		$ 240	$ 960
Short-term investments | Certificates of deposit | Maximum
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities contractual maturity		1 year	1 year
Short-term investments | Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$ 66,759	$ 49,280
Gross Unrealized Gains	[1]	0	3
Gross Unrealized Losses	[1]	(24)	(38)
Aggregate Estimated Fair Value		$ 66,735	$ 49,245
Short-term investments | Commercial paper | Maximum
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities contractual maturity		1 year	1 year
Short-term investments | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$ 163,870	$ 168,548
Gross Unrealized Gains	[1]	3	3
Gross Unrealized Losses	[1]	(131)	(117)
Aggregate Estimated Fair Value		$ 163,742	$ 168,434
Short-term investments | Corporate debt securities | Maximum
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities contractual maturity		1 year	1 year
Short-term investments | Domestic and foreign government agencies debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$ 12,503	$ 5,448
Gross Unrealized Gains	[1]	0	0
Gross Unrealized Losses	[1]	(21)	(4)
Aggregate Estimated Fair Value		$ 12,482	$ 5,444
Short-term investments | Domestic and foreign government agencies debt securities | Maximum
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities contractual maturity		1 year	1 year
Long-term investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$ 210,620	$ 43,655
Gross Unrealized Gains	[1]	0	0
Gross Unrealized Losses	[1]	(361)	(165)
Aggregate Estimated Fair Value		210,259	43,490
Long-term investments | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		199,615	36,149
Gross Unrealized Gains	[1]	0	0
Gross Unrealized Losses	[1]	(345)	(147)
Aggregate Estimated Fair Value		$ 199,270	$ 36,002
Long-term investments | Corporate debt securities | Minimum
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities contractual maturity		1 year	1 year
Long-term investments | Corporate debt securities | Maximum
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities contractual maturity		2 years	2 years
Long-term investments | Domestic and foreign government agencies debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		$ 11,005	$ 7,506
Gross Unrealized Gains	[1]	0	0
Gross Unrealized Losses	[1]	(16)	(18)
Aggregate Estimated Fair Value		$ 10,989	$ 7,488
Long-term investments | Domestic and foreign government agencies debt securities | Minimum
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities contractual maturity		1 year	1 year
Long-term investments | Domestic and foreign government agencies debt securities | Maximum
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities contractual maturity		2 years	2 years
[1]	Unrealized gains and losses are included in other comprehensive loss.

Gross Unrealized Losses and Fai

Gross Unrealized Losses and Fair Value Available-For-Sale Investments in Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value	$ 407,946	$ 241,956
Less Than 12 Months, Unrealized Losses	(504)	(321)
12 Months or Greater, Estimated Fair Value	21,781	9,144
12 Months or Greater, Unrealized Losses	(33)	(3)
Total Estimated Fair Value	429,727	251,100
Total Unrealized Losses	(537)	(324)
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value	66,735	43,781
Less Than 12 Months, Unrealized Losses	(24)	(38)
12 Months or Greater, Estimated Fair Value	0	0
12 Months or Greater, Unrealized Losses	0	0
Total Estimated Fair Value	66,735	43,781
Total Unrealized Losses	(24)	(38)
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value	325,223	185,243
Less Than 12 Months, Unrealized Losses	(463)	(261)
12 Months or Greater, Estimated Fair Value	14,298	9,144
12 Months or Greater, Unrealized Losses	(13)	(3)
Total Estimated Fair Value	339,521	194,387
Total Unrealized Losses	(476)	(264)
Domestic and foreign government agencies debt securities
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value	15,988	12,932
Less Than 12 Months, Unrealized Losses	(17)	(22)
12 Months or Greater, Estimated Fair Value	7,483	0
12 Months or Greater, Unrealized Losses	(20)	0
Total Estimated Fair Value	23,471	12,932
Total Unrealized Losses	$ (37)	$ (22)

Assets Measured at Fair Value o

Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	$ 453.4	$ 267.6
Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	512.5	307.3
Short-term investments | Cash and money market fund
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	269.4	73.6
Short-term investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0.2	1
Short-term investments | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	66.7	49.2
Short-term investments | Domestic and foreign government agencies debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	12.5	5.4
Short-term investments | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	163.7	178.1
Long-term investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	3	4.9
Long-term investments | Domestic and foreign government agencies debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	11	7.5
Long-term investments | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	199.3	36
Investments Including Cash Equivalents And Restricted Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	725.8	355.7
Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	272.4	88.1
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0.2	1
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	269.6	74.6
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments | Cash and money market fund
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	269.4	73.6
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0.2	1
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments | Domestic and foreign government agencies debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Long-term investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	3	4.9
Quoted Prices in Active Markets for Identical Assets (Level 1) | Long-term investments | Domestic and foreign government agencies debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Long-term investments | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Investments Including Cash Equivalents And Restricted Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	272.6	79.5
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	272.4	78.5
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	453.2	266.6
Significant Other Observable Inputs (Level 2) | Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	242.9	232.7
Significant Other Observable Inputs (Level 2) | Short-term investments | Cash and money market fund
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Other Observable Inputs (Level 2) | Short-term investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Other Observable Inputs (Level 2) | Short-term investments | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	66.7	49.2
Significant Other Observable Inputs (Level 2) | Short-term investments | Domestic and foreign government agencies debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	12.5	5.4
Significant Other Observable Inputs (Level 2) | Short-term investments | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	163.7	178.1
Significant Other Observable Inputs (Level 2) | Long-term investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Other Observable Inputs (Level 2) | Long-term investments | Domestic and foreign government agencies debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	11	7.5
Significant Other Observable Inputs (Level 2) | Long-term investments | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	199.3	36
Significant Other Observable Inputs (Level 2) | Investments Including Cash Equivalents And Restricted Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	453.2	276.2
Significant Other Observable Inputs (Level 2) | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	9.6
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Short-term investments | Cash and money market fund
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Short-term investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Short-term investments | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Short-term investments | Domestic and foreign government agencies debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Short-term investments | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Long-term investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Long-term investments | Domestic and foreign government agencies debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Long-term investments | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Investments Including Cash Equivalents And Restricted Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Significant Unobservable Inputs (Level 3) | Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	$ 0	$ 0

Compensation Expense Related to

Compensation Expense Related to Share-Based Compensation (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	$ 10.2	$ 6.3	$ 29.1	$ 20.5
Sales, General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	6.5	3.5	18.2	11.8
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	$ 3.7	$ 2.8	$ 10.9	$ 8.7

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option exercised				1	0.3
Cash received from stock option exercises				$ 8.3	$ 2.3
Common stock issued pursuant to the vesting of restricted stock units (RSUs)				0.3	0.3
Common stock issued pursuant to the vesting of performance-based restricted stock units (PRSUs)		0.2
Stock options granted				1.6	1
Share-based compensation expense	$ 10.2		$ 6.3	$ 29.1	$ 20.5
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	50.9			$ 50.9
Stock vesting period				2 years 9 months 19 days
Stock vesting period				4 years	4 years
Share-based compensation expense				$ 18.7	$ 13.1
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	32.7			$ 32.7
Stock vesting period				2 years 10 months 24 days
Stock vesting period				4 years	4 years
Share-based compensation expense				$ 10.4
Restricted stock units granted				0.6	0.3
Performance-based RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	$ 7.5			$ 7.5
RSU with performance-based vesting requirements outstanding	0.2			0.2
Stock vesting period					4 years
Share-based compensation expense					$ 7.4
Restricted stock units granted					0.2

Weighted-Average Assumptions fo

Weighted-Average Assumptions for Stock Option Grants using Black-Scholes Option-Pricing Model (Detail) - Stock Options	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.80%	1.10%	2.00%	1.40%
Expected volatility of common stock	59.60%	59.30%	58.20%	60.00%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Expected option term	5 years	5 years	5 years 8 months 12 days	5 years 7 months 6 days

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2017shares
February Two Thousand Seventeen Shelf Registration [Member]
Class of Stock [Line Items]
Number of securities sold	0

Real Estate - Additional Inform

Real Estate - Additional Information (Detail) ft² in Thousands, $ in Millions	1 Months Ended	3 Months Ended				9 Months Ended
	Dec. 31, 2007USD ($)Building	Sep. 30, 2017USD ($)RenewalOptions	Jun. 30, 2017USD ($)	Sep. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Sep. 30, 2017USD ($)ft²RenewalOptionsLease_Agreements	Sep. 30, 2016USD ($)	Dec. 31, 2008USD ($)
Real Estate Properties [Line Items]
Sale of facility and associated real property	$ 109
Mortgage debt retired	47.7
Cash received net of transaction costs and debt retirement	$ 61
Leaseback transaction lease period	12 years
Number of building leased | Building	2
Net deferred gain on real estate sale		$ 9				$ 9		$ 39.1
Deferred gain recognized on real estate sale		0.2		$ 0.9		$ 2	$ 2.6
Lease expiration year						2,029
Lease security deposit		4.7				$ 4.7
Letter of credit		$ 3				$ 3
Percentage of management fee included in the base annual rent						3.50%
Lease extension period						10 years
Number of times to renew the lease contract | RenewalOptions		2				2
Subleased area | ft²						16
Rental income from sublease agreement						$ 0.6
Amended Lease Term [Member]
Real Estate Properties [Line Items]
Lease expiration date						Dec. 31, 2029
Percentage reduction in base rental						8.00%
Tenant improvement allowances		$ 13.1				$ 13.1
Lease security deposit		$ 3				$ 3
Sublease
Real Estate Properties [Line Items]
Number of sublease agreements | Lease_Agreements						1
Reversal of cease use expense			$ 0.5		$ 0.8
Second Sublease
Real Estate Properties [Line Items]
Lease expiration date						2018-03

Changes to Accrued Cease-Use Li

Changes to Accrued Cease-Use Liability (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Beginning balance	$ 181	$ 972	$ 853	$ 1,983
Change in estimate	0	0	(544)	(830)
Payments	(60)	(58)	(188)	(239)
Ending balance	$ 121	$ 914	$ 121	$ 914

Convertible Senior Notes - Addi

Convertible Senior Notes - Additional Information (Detail) $ / shares in Units, $ in Thousands	May 02, 2017USD ($)	Sep. 30, 2017USD ($)d$ / shares
Debt Instrument [Line Items]
Convertible senior notes principal amount		$ 517,500
Proceeds from Senior Convertible Notes		$ 502,781
2.25% Convertible Senior Notes due 2024
Debt Instrument [Line Items]
Convertible senior notes principal amount	$ 517,500
Convertible senior notes interest percentage	2.25%
Convertible senior notes convertible latest date		May 15, 2024
Convertible senior notes interest rate	2.25%
Proceeds from Senior Convertible Notes	$ 502,800
Threshold common stock trading days | d		20
Threshold consecutive common stock trading days | d		30
Threshold percentage of common stock price trigger		130.00%
Minimum percentage of common stock price trigger		98.00%
Conversion Observation Period		25 days
Convertible senior notes convertible in to shares		0.00131711
Convertible senior notes conversion price | $ / shares		$ 75.92
Market Price of Common stock | $ / shares		$ 53.28
Convertible senior note premium		42.50%
Convertible senior notes redemption rate		100.00%
Fair value of convertible senior note as percentage of principal amount		113.75%
Convertible senior note carrying value of the liability component		$ 368,300
Convertible senior note assumed borrowing rate		7.50%
Convertible senior note carrying value of the equity component		$ 149,200
Convertible senior notes		7 years
Transaction cost related to issuance of convertible senior note		$ 14,700

Convertible Senior Notes - Debt

Convertible Senior Notes - Debt Net of Discount and Deferred Financing (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Debt Disclosure [Abstract]
Principal	$ 517,500
Deferred financing costs	(9,975)
Debt discount, net	(142,415)
Net carrying amount	$ 365,110	$ 0

Loss Per Common Share - Additio

Loss Per Common Share - Additional Information (Detail) - USD ($) $ in Thousands, shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Net loss	$ (11,125)	$ (36,887)	$ (149,436)	$ (96,431)
Shares of common stock excluded from computation of diluted earnings per share outstanding	0.2	0.1	0.4	0.4

BIAL Agreement - Additional Inf

BIAL Agreement - Additional Information (Detail) - B I A L - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Mar. 31, 2017	Sep. 30, 2017
License Agreement [Line Items]
License agreement date		Feb. 9, 2017
Up-front license fees	$ (30)
Milestone payables	$ 115

Concentration Risk - Additional

Concentration Risk - Additional Information (Detail) - Customer Concentration Risk [Member]	3 Months Ended
	Sep. 30, 2017Customer
Sales Revenue, Goods, Net
Concentration Risk [Line Items]
Number of customers	3
Accounts Receivable [Member]
Concentration Risk [Line Items]
Number of customers	3

Subsequent Event - Additional I

Subsequent Event - Additional Information (Detail) - AbbVie - Subsequent Event $ in Millions	1 Months Ended
	Oct. 31, 2017USD ($)
Subsequent Event [Line Items]
Collaborative arrangement even-based payment amount	$ 30
Collaborative arrangement even-based payment period	30 days