Neurocrine Biosciences (NBIX) 10-Q 30 Apr 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 24, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	NBIX
Entity Registrant Name	NEUROCRINE BIOSCIENCES INC
Entity Central Index Key	914475
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		85,417,797

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$170,262	$31,014
Short-term investments, available for sale	199,745	162,795
Receivables under collaboration agreements	30,030
Other current assets	4,916	4,394
Total current assets	404,953	198,203
Property and equipment, net	2,543	2,507
Long-term investments, available for sale	115,452	37,492
Restricted cash	4,831	4,831
Total assets	527,779	243,033
Current liabilities:
Accounts payable	1,270	246
Accrued liabilities	9,938	11,508
Current portion of cease-use liability	479	467
Current portion of deferred rent	152	119
Current portion of deferred gain on sale of real estate	3,348	3,324
Total current liabilities	15,187	15,664
Deferred gain on sale of real estate	13,468	14,322
Deferred revenue	10,231	0
Deferred rent	1,817	1,877
Cease-use liability	2,086	2,211
Other liabilities	260	260
Total liabilities	43,049	34,334
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; 110,000,000 shares authorized; issued and outstanding shares were 85,372,303 as of March 31, 2015 and 76,465,942 as of December 31, 2014	85	76
Additional paid-in capital	1,312,321	1,035,205
Accumulated other comprehensive loss	-179	-277
Accumulated deficit	-827,497	-826,305
Total stockholders' equity	484,730	208,699
Total liabilities and stockholders' equity	$527,779	$243,033

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Preferred stock, par value	$0.00	$0.00
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	$0.00	$0.00
Common stock, shares authorized	110,000,000	110,000,000
Common stock, shares issued	85,372,303	76,465,942
Common stock, shares outstanding	85,372,303	76,465,942

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Comprehensive Loss (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenues:
License fees	$19,769	$0
Total revenues	19,769	0
Operating expenses:
Research and development	16,575	8,572
General and administrative	5,482	4,153
Total operating expenses	22,057	12,725
Loss from operations	-2,288	-12,725
Other income:
Gain (loss) on sale/disposal of assets	9	-10
Deferred gain on real estate	830	804
Investment income, net	257	89
Total other income	1,096	883
Net loss	-1,192	-11,842
Net loss per common share:
Basic and diluted	($0.01)	($0.17)
Shares used in the calculation of net loss per common share:
Basic and diluted	80,349	70,260
Other comprehensive loss:
Net loss	-1,192	-11,842
Net unrealized gains/(losses) on available-for-sale securities	98	-199
Comprehensive loss	($1,094)	($12,041)

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	($1,192)	($11,842)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	244	178
Gain on sale of assets	-839	-794
Deferred revenues	10,231	0
Deferred rent	-27	6
Amortization of premiums on investments	1,011	617
Non-cash share-based compensation expense	3,600	2,447
Change in operating assets and liabilities:
Accounts receivable under collaboration agreements and other assets	-30,552	850
Accounts payable and accrued liabilities	-546	-1,127
Cease-use liability	-113	-102
Net cash used in operating activities	-18,183	-9,767
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of investments	-159,221	-108,907
Sales and maturities of investments	43,398	43,391
Proceeds from sales of property and equipment	9	40
Purchases of property and equipment	-280	-255
Net cash used in investing activities	-116,094	-65,731
CASH FLOWS FROM FINANCING ACTIVITIES
Issuance of common stock	273,525	136,241
Net cash provided by financing activities	273,525	136,241
Net increase in cash and cash equivalents	139,248	60,743
Cash and cash equivalents at beginning of the period	31,014	44,789
Cash and cash equivalents at end of the period	$170,262	$105,532

ORGANIZATION_AND_SIGNIFICANT_A

ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES	1. ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES
	Description of Business. Neurocrine Biosciences, Inc. (the Company or Neurocrine) was incorporated in California in 1992 and reincorporated in Delaware in 1996. The Company discovers and develops innovative and life-changing pharmaceuticals, in diseases with high unmet medical needs, through its novel research and development (R&D) platform, focused on neurological and endocrine based diseases and disorders. The Company’s two lead late-stage clinical programs are elagolix, a gonadotropin-releasing hormone (GnRH) antagonist for women’s health that is partnered with AbbVie Inc. (AbbVie), and a vesicular monoamine transporter 2 (VMAT2) inhibitor for the treatment of movement disorders.
	Basis of Presentation. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (GAAP) for interim financial information and with the instructions of the Securities and Exchange Commission (SEC) on Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by GAAP for complete financial statements. In the opinion of management, the condensed consolidated financial statements include all adjustments necessary, which are of a normal and recurring nature, for the fair presentation of the Company’s financial position and of the results of operations and cash flows for the periods presented. The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries.
	These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2014 included in the Company’s Annual Report on Form 10-K filed with the SEC. The results of operations for the interim period shown in this report are not necessarily indicative of the results that may be expected for any other interim period or for the full year. The balance sheet at December 31, 2014 has been derived from the audited financial statements at that date, but does not include all of the information and footnotes required by GAAP for complete financial statements.
	Impact of Recently Issued Accounting Standards. In May 2014, the Financial Accounting Standards Board (FASB) amended the existing accounting standards for revenue recognition, which outlines a comprehensive revenue recognition model and supersedes most current revenue recognition guidance. The new standard requires a company to recognize revenue upon transfer of goods or services to a customer at an amount that reflects the expected consideration to be received in exchange for those goods or services. The amended guidance defines a five-step approach for recognizing revenue, which may require a company to use more judgment and make more estimates than under the current guidance. The amended guidance as currently issued will be effective for the Company starting in 2017. On April 1, 2015, the FASB voted to propose a one-year deferral to the effective date, but to permit entities to adopt one year earlier if they choose (i.e., the original effective date). The proposal will be subject to the FASB’s due process requirement, which includes a period for public comments. The new standard allows for two methods of adoption: (a) full retrospective adoption, meaning the standard is applied to all periods presented, or (b) modified retrospective adoption, meaning the cumulative effect of applying the new standard is recognized as an adjustment to the opening retained earnings balance. The Company is in the process of determining the adoption method as well as the effects the adoption will have on its consolidated financial statements.
	Use of Estimates. The preparation of the condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and the accompanying notes. Actual results could differ from those estimates.

REVENUE_RECOGNITION_AND_SIGNIF

REVENUE RECOGNITION AND SIGNIFICANT COLLABORATIVE RESEARCH AND DEVELOPMENT AGREEMENTS	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
REVENUE RECOGNITION AND SIGNIFICANT COLLABORATIVE RESEARCH AND DEVELOPMENT AGREEMENTS	2. REVENUE RECOGNITION AND SIGNIFICANT COLLABORATIVE RESEARCH AND DEVELOPMENT AGREEMENTS
	Revenue Recognition Policy. The Company recognizes revenue for the performance of services when each of the following four criteria is met: (i) persuasive evidence of an arrangement exists; (ii) services are rendered or products are delivered; (iii) the sales price is fixed or determinable; and (iv) collectability is reasonably assured.
	Effective in 2011, the Company follows 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 our 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 license fees; funding of research and/or development efforts; amounts due upon the achievement of specified milestones; manufacturing and royalties on future product sales.
	The ASC provides guidance relating to the separation of deliverables included in an arrangement into different units of accounting and the allocation of arrangement 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 payments when licensing its intellectual property, which often occurs in conjunction with a research and development agreement. The Company recognizes revenue attributed to the license upon delivery, provided that the license has stand-alone value.
	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. 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). On March 31, 2015, the Company entered into a collaboration and license agreement with Mitsubishi Tanabe for the development and commercialization of NBI-98854 for movement disorders in Japan and other select Asian markets. Payments to the Company under this agreement include an up-front license fee of $30 million, up to $85 million in development and commercialization event-based payments, payments for the manufacture of pharmaceutical products, and royalties on product sales in select territories in Asia. Under the terms of the agreement, Mitsubishi Tanabe is responsible for all third-party development, marketing and commercialization costs in Japan and other select Asian markets with the exception of a single Huntington’s chorea clinical trial to be performed by the Company, at an estimated cost of approximately $12 million, should Mitsubishi Tanabe request the clinical trial. The Company will be entitled to a percentage of sales of NBI-98854 in Japan and other select Asian markets for the longer of ten years or the life of the related patent rights.
	Under the terms of the Company’s agreement with Mitsubishi Tanabe, the collaboration effort between the parties to advance NBI-98854 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 NBI-98854 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: NBI-98854 technology license and existing know-how, development activities to be performed as part of the collaboration, and the manufacture of pharmaceutical products. The respective standalone value from each of these deliverables has been determined by applying the BESP method and the revenue was allocated based on the relative selling price method with revenue recognition timing to be determined either by delivery or the provision of services.
	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 was delivered on the effective date of the agreement.
	For the quarter ended March 31, 2015, the Company recognized revenue under this agreement of $19.8 million associated with the delivery of a technology license and existing know-how. In accordance with the Company’s continuing performance obligations, $10.2 million of the $30 million up-front payment is being deferred and recognized in future periods. Under the terms of the agreement, there is no general obligation to return the up-front payment for any non-contingent deliverable.
	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.
	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). In June 2010, the Company announced an exclusive worldwide collaboration with AbbVie to develop and commercialize elagolix and all next-generation gonadotropin-releasing hormone (GnRH) antagonists (collectively, GnRH Compounds) for women’s and men’s health. AbbVie made an upfront payment of $75 million and has agreed to make additional development and regulatory event-based payments of up to $480 million and up to an additional $50 million in commercial event-based payments. The Company has assessed event-based payments under the revised authoritative guidance for research and development milestones and determined that event-based payments prior to commencement of a Phase III clinical study, as defined in the agreement, meet the definition of a milestone in accordance with authoritative guidance as (i) they are events that can only be achieved in part on the Company’s past performance, (ii) there is substantive uncertainty at the date the arrangement was entered into that the event will be achieved and (iii) they result in additional payments being due to the Company. Development and regulatory event-based payments subsequent to the commencement of a Phase III clinical study, however, currently do not meet these criteria as their achievement is based on the performance of AbbVie. As of March 31, 2015, $500 million remains outstanding in future event-based payments under the agreement. However, none of the remaining event-based payments meet the definition of a milestone in accordance with authoritative accounting guidance.
	Under the terms of the agreement, AbbVie is responsible for all third-party development, marketing and commercialization costs. The Company received funding for certain internal collaboration expenses, which included reimbursement from AbbVie for internal and external expenses related to the GnRH Compounds, through the end of 2012. 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. Under the terms of the Company’s agreement with AbbVie, the collaboration effort between the parties to advance GnRH Compounds towards commercialization was governed by a joint development committee with representatives from both the Company and AbbVie. The Company’s participation in the joint development committee was determined to be a substantive deliverable under the contract, and therefore, the upfront payment was deferred and recognized over the term of the joint development committee, which was completed, as scheduled, in December 2012. 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.

INVESTMENTS

INVESTMENTS	3 Months Ended
	Mar. 31, 2015
Investments Schedule [Abstract]
INVESTMENTS	3. INVESTMENTS
	Available-for-sale securities are carried at fair value, with the unrealized gains and losses reported in comprehensive loss. The amortized cost of debt securities in this category is adjusted for amortization of premiums and accretion of discounts to maturity. Such amortization and accretion is included in interest income. Realized gains and losses and declines in value judged to be other-than-temporary, if any, on available-for-sale securities are included in other income or expense. The cost of securities sold is based on the specific identification method. Interest and dividends on securities classified as available-for-sale are included in interest income.
	Investments consist of the following (in thousands):
			March 31,		December 31,
			2015		2014
	Certificates of deposit		$	16,521	$	17,438
	Commercial paper			11,943		7,498
	Corporate debt securities			280,573		174,323
	Securities of government sponsored entities			6,160		1,028
	Total investments		$	315,197	$	200,287
	The following is a summary of investments classified as available-for-sale securities (in thousands):
			Contractual		Amortized			Gross		Gross			Aggregate
			Maturity		Cost			Unrealized		Unrealized			Estimated
			(in years)					Gains(1)		Losses(1)			Fair
													Value
	March 31, 2015:
	Classified as current assets:
	Certificates of deposit			Less than 1	$	9,320		$	2	$	(2	)	$	9,320
	Commercial paper			Less than 1		11,948			6		(11	)		11,943
	Corporate debt securities			Less than 1		178,406			14		(91	)		178,329
	Securities of government-sponsored entities			Less than 1		153			—		—			153
	Total short-term available-for-sale securities				$	199,827		$	22	$	(104	)	$	199,745
	Classified as non-current assets:
	Certificates of deposit			1 to 2	$	7,200		$	2	$	(1	)	$	7,201
	Corporate debt securities			1 to 2		102,345			14		(115	)		102,244
	Securities of government-sponsored entities			1 to 2		6,004			3		—			6,007
	Total long-term available-for-sale securities				$	115,549		$	19	$	(116	)	$	115,452
	December 31, 2014:
	Classified as current assets:
	Certificates of deposit			Less than 1	$	9,072		$	—	$	(6	)	$	9,066
	Commercial paper			Less than 1		7,497			1		—			7,498
	Corporate debt securities			Less than 1		145,321			5		(123	)		145,203
	Securities of government-sponsored entities			Less than 1		1,029			—		(1	)		1,028
	Total short-term available-for-sale securities				$	162,919		$	6	$	(130	)	$	162,795
	Classified as non-current assets:
	Certificates of deposit			1 to 2	$	8,400		$	—	$	(28	)	$	8,372
	Corporate debt securities			1 to 2		29,245			—		(125	)		29,120
	Total long-term available-for-sale securities				$	37,645		$	—	$	(153	)	$	37,492
	-1	Unrealized gains and losses are included in other comprehensive loss.
	The following table presents information about available-for-sale investments in an unrealized loss position (in thousands):
			Less Than 12 Months					12 Months or Greater					Total
			Estimated		Unrealized			Estimated		Unrealized			Estimated		Unrealized
			Fair		Losses			Fair		Losses			Fair		Losses
			Value					Value					Value
	March 31, 2015:
	Certificates of deposit		$	6,437	$	(3	)	$	240	$	—		$	6,677	$	(3	)
	Commercial paper			4,974		(11	)		—		—			4,974		(11	)
	Corporate debt securities			204,039		(192	)		6,371		(14	)		210,410		(206	)
	Total		$	215,450	$	(206	)	$	6,611	$	(14	)	$	222,061	$	(220	)
	December 31, 2014:
	Certificates of deposit		$	16,957	$	(34	)	$	—	$	—		$	16,957	$	(34	)
	Corporate debt securities			149,477		(248	)		—		—			149,477		(248	)
	Securities of government-sponsored entities			1,028		(1	)		—		—			1,028		(1	)
	Total		$	167,462	$	(283	)	$	—	$	—		$	167,462	$	(283	)
	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 investments for other-than-temporary declines in fair value below cost basis each quarter and whenever events or changes in circumstances indicate that the cost basis of an asset may not be recoverable. This evaluation is based on a number of factors, including the length of time and the extent to which the fair value has been below the cost basis and adverse conditions related specifically to the security, including any changes to the credit rating of the security, and the intent to sell, or whether the Company will more likely than not be required to sell the security before recovery of its amortized cost basis. The assessment of whether a security is other-than-temporarily impaired could change in the future due to new developments or changes in assumptions related to any particular security. As of March 31, 2015 and December 31, 2014, the Company believes the cost bases for available-for-sale investments were recoverable in all material respects.

FAIR_VALUE_MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	4. 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 investments within Level 1 or Level 2. The fair value of the Company’s high quality investment grade corporate debt securities is determined using proprietary valuation models and analytical tools. These valuation models and analytical tools use market pricing or prices for similar instruments that are both objective and publicly available, including matrix pricing or reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids and/or offers. The Company did not reclassify any investments between levels in the fair value hierarchy during the three months ended March 31, 2015.
	The Company’s assets which were measured at fair value on a recurring basis as of March 31, 2015 and December 31, 2014 were determined using the inputs described above and are as follows (in millions):
					Fair Value Measurements Using
		Carrying			Quoted Prices  in			Significant Other			Significant
		Value			Active			Observable			Unobservable
					Markets for			Inputs			Inputs
					Identical Assets			(Level 2)			(Level 3)
					(Level 1)
	March 31, 2015:
	Classified as current assets:
	Cash and money market funds	$	136.4		$	136.4		$	—		$	—
	Certificates of deposit		9.3			9.3			—			—
	Commercial paper		17.4			—			17.4			—
	Securities of government-sponsored entities		0.2			—			0.2			—
	Corporate debt securities		206.7			—			206.7			—
	Subtotal		370			145.7			224.3			—
	Classified as long-term assets:
	Certificates of deposit		12.1			12.1			—			—
	Corporate debt securities		102.2			—			102.2			—
	Securities of government-sponsored entities		6			—			6			—
	Total		490.3			157.8			332.5			—
	Less cash, cash equivalents and restricted cash		(175.1	)		(141.2	)		(33.9	)		—
	Total investments	$	315.2		$	16.6		$	298.6		$	—
	December 31, 2014:
	Classified as current assets:
	Cash and money market funds	$	28.7		$	28.7		$	—		$	—
	Certificates of deposit		9.1			9.1			—			—
	Commercial paper		7.5			—			7.5			—
	Securities of government-sponsored entities		1.5			—			1.5			—
	Corporate debt securities		147			—			147			—
	Subtotal		193.8			37.8			156			—
	Classified as long-term assets:
	Certificates of deposit		13.2			13.2			—			—
	Corporate debt securities		29.1			—			29.1			—
	Total		236.1			51			185.1			—
	Less cash, cash equivalents and restricted cash		(35.8	)		(33.5	)		(2.3	)		—
	Total investments	$	200.3		$	17.5		$	182.8		$	—

SHAREBASED_COMPENSATION

SHARE-BASED COMPENSATION	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
SHARE-BASED COMPENSATION	5. 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
		March 31,
		2015			2014
	General and administrative	$	1.7		$	1.2
	Research and development		1.9			1.2
	Total share-based compensation expense	$	3.6		$	2.4
	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 March 31, 2015, total unrecognized estimated compensation cost related to non-vested stock options and non-vested RSUs, that vest over a given service period, granted prior to that date was $26.3 million and $19.4 million, respectively, which is expected to be recognized over a weighted average period of approximately 3.2 years and 3.4 years, respectively. Additionally, the Company has approximately 0.5 million PRSUs outstanding. The total unrecognized estimated compensation cost related to these PRSUs is $11.0 million and is expected to be recognized at the point when the performance conditions have been achieved, which is when these events will become probable.
	During the three months ended March 31, 2015 and 2014, stock options to purchase approximately 0.7 million and 0.4 million shares of the Company’s common stock were exercised, respectively. The cash received by the Company from stock option exercises during the three months ended March 31, 2015 and 2014 was approximately $2.8 million and $3.0 million, respectively. The Company also issued approximately 0.2 million and 0.1 million shares of common stock pursuant to the vesting of RSUs during the three months ended March 31, 2015 and 2014, respectively.
	Stock Option Assumptions
	The Company granted stock options to purchase approximately 0.7 million and 0.8 million shares of the Company’s common stock during the three months ended March 31, 2015 and 2014, respectively. These stock options generally vest monthly over a four-year period. The exercise price of all stock options granted during the three months ended March 31, 2015 and 2014 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
		March 31,
		2015		2014
	Risk-free interest rate	1.60%		2.30%
	Expected volatility of common stock	66.60%		71.30%
	Dividend yield	0.00%		0.00%
	Expected option term	6.7 years		7.1 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 three months ended March 31, 2015 and 2014, share-based compensation expense related to stock options was $2.4 million and $1.9 million, respectively.
	Restricted Stock Units
	During the three months ended March 31, 2015, the Company granted approximately 0.4 million RSUs that vest annually over a four year period. Additionally, during the three months ended March 31, 2015 and 2014, the Company granted 50,000 and 475,000 PRSUs, respectively. These PSRUs vest based on the achievement of pre-defined Company-specific performance criteria and expire approximately five years from the grant date. As the performance based criteria for vesting for the PRSUs is not currently probable, no associated expense has been recorded for these PRSUs during the three months ended March 31, 2015. The fair value of RSUs is estimated based on the closing sale price of the Company’s common stock on the date of the RSU grant. For the three months ended March 31, 2015 and 2014, share-based compensation expense related to RSUs was $1.2 million and $0.5 million, respectively.

STOCKHOLDERS_EQUITY

STOCKHOLDERS' EQUITY	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
STOCKHOLDERS' EQUITY	6. STOCKHOLDERS’ EQUITY
	Equity Financing
	In February 2015, the Company completed a public offering of common stock in which the Company sold 8.0 million shares of its common stock at an offering price of $36.00 per share. The net proceeds generated from this transaction, after underwriting discounts and commissions and offering costs, were approximately $270.7 million.
	In February 2014, the Company completed a public offering of common stock in which the Company sold 8.0 million shares of its common stock at an offering price of $17.75 per share. The net proceeds generated from this transaction, after underwriting discounts and commissions and offering costs, were approximately $133.2 million.
	Shelf Registration Statements
	In February 2014, 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 shares of its common stock from time to time. As of March 31, 2015, the Company had sold 16.0 million shares under this shelf registration statement.
	In December 2012, the SEC declared effective a shelf registration statement filed by the Company in November 2012. The shelf registration statement allows the Company to issue shares of its common stock from time to time for an aggregate initial offering price of up to $150 million. As of March 31, 2015, the Company had not sold any shares under this shelf registration statement.
	The specific terms of future offerings, if any, under any of the shelf registration statements would be established at the time of such offerings.

REAL_ESTATE

REAL ESTATE	3 Months Ended
	Mar. 31, 2015
Leases [Abstract]
REAL ESTATE	7. 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) with DMH Campus Investors, LLC (DMH) 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 which it vacated the Front Building, but continues 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 $0.8 million of the deferred gain during each of the three month periods ended March 31, 2015 and 2014, respectively, and will recognize the remaining $16.8 million of the deferred gain over the initial Lease term which will expire at the end of 2019.
	Under the terms of the Lease and the Amendments, the Company pays 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. In lieu of a cash security deposit under the Lease, Wells Fargo Bank, N.A. issued on the Company’s behalf a letter of credit in the amount of $4.6 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 terms.
	In December 2010, the Company entered into a sublease agreement (Sublease) for approximately 16,000 square feet of the Rear Building. The Sublease is expected to result in approximately $0.6 million of rental income per year over the three year initial term of the Sublease and is recorded as an offset to rent expense. The Sublease provides an option to extend for two one-year renewal periods. The income generated under the Sublease is lower than the Company’s financial obligation under the Lease for the Rear Building with DMH, as determined on a per square foot basis. Consequently, at December 31, 2010 the Company was required to record a cease-use liability for the net present value estimated difference between the expected income to be generated under the Sublease and future subleases and the Lease obligation over the remaining term of the Lease for the space that is occupied by the subtenant. This transaction resulted in $2.5 million of gross cease-use expense, and a reversal of $173,000 in associated deferred rent, each being recorded in December 2010. In August 2012, the Company extended the terms of the Sublease and increased the leased square footage to approximately 17,000 square feet. This transaction resulted in approximately $150,000 of gross cease-use expense, and a reversal of $15,000 in associated deferred rent, each being recorded in September 2012.
	In September 2011, the Company entered into a second sublease agreement (Second Sublease) for approximately 3,300 square feet of space in the Rear Building. The Second Sublease is expected to result in approximately $0.1 million in rental income per year over the three year term and is recorded as an offset to rent expense. The Second Sublease provides an option to extend for a one-year renewal period, and was extended for the one-year renewal period. Similar to the Sublease, the Second Sublease resulted in $0.3 million of gross cease-use expense, and a reversal of $47,000 in associated deferred rent, each being recorded in September 2011.
	In November 2012, the Company entered into a third sublease agreement (Third Sublease) for approximately 14,000 square feet of space in the Rear Building. The Third Sublease is expected to result in approximately $0.5 million in rental income per year over the three and a half year term and is recorded as an offset to rent expense. The Third Sublease provides the subtenant with an option to extend the term for two one-year renewal periods. Similar to the previous subleases, the Third Sublease resulted in $1.2 million of gross cease-use expense, and a reversal of $250,000 in associated deferred rent, each being recorded in December 2012.
	The following table sets forth changes to the accrued cease-use liability during the three months ended March 31, 2015 and 2014 (in thousands):
		Three Months Ended
		March 31,
		2015			2014
	Beginning balance	$	2,678		$	3,096
	Payments		(113	)		(102	)
	Ending balance	$	2,565		$	2,994

LOSS_PER_COMMON_SHARE

LOSS PER COMMON SHARE	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
LOSS PER COMMON SHARE	8. 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, are excluded from the diluted loss per share calculation because of their anti-dilutive effect.
	For the three months ended March 31, 2015, the Company realized a net loss of $1.2 million. Potentially dilutive securities totaled approximately 3.9 million for the three months ended March 31, 2015. Options to purchase approximately 0.1 million shares of common stock were outstanding during the three months ended March 31, 2015 with an exercise price greater than the average market price of the underlying common shares.
	For the three months ended March 31, 2014, the Company realized a net loss of $11.8 million. Potentially dilutive securities totaled approximately 3.0 million for the three months ended March 31, 2014. Options to purchase approximately 0.9 million shares of common stock were outstanding during the three months ended March 31, 2014 with an exercise price greater than the average market price of the underlying common shares.

RESEARCH_AND_DEVELOPMENT

RESEARCH AND DEVELOPMENT	3 Months Ended
	Mar. 31, 2015
Research and Development [Abstract]
RESEARCH AND DEVELOPMENT	9. RESEARCH AND DEVELOPMENT
	Research and development (R&D) expenses consists 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 arrangements. In addition, the Company funds R&D at other companies and research institutions under agreements, which are generally cancelable. The Company reviews and accrues clinical trial expenses based on work performed, which relies on estimates of total costs incurred based on patient enrollment, completion of patient studies and other events. The Company follows this method since reasonably dependable estimates of the costs applicable to various stages of a research agreement or clinical trial can be made. Accrued clinical costs are subject to revisions as trials progress. Revisions are charged to expense in the period in which the facts that give rise to the revision become known.

ORGANIZATION_AND_SIGNIFICANT_A1

ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Description of Business	Description of Business. Neurocrine Biosciences, Inc. (the Company or Neurocrine) was incorporated in California in 1992 and reincorporated in Delaware in 1996. The Company discovers and develops innovative and life-changing pharmaceuticals, in diseases with high unmet medical needs, through its novel research and development (R&D) platform, focused on neurological and endocrine based diseases and disorders. The Company’s two lead late-stage clinical programs are elagolix, a gonadotropin-releasing hormone (GnRH) antagonist for women’s health that is partnered with AbbVie Inc. (AbbVie), and a vesicular monoamine transporter 2 (VMAT2) inhibitor for the treatment of movement disorders.
Basis of Presentation	Basis of Presentation. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (GAAP) for interim financial information and with the instructions of the Securities and Exchange Commission (SEC) on Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and disclosures required by GAAP for complete financial statements. In the opinion of management, the condensed consolidated financial statements include all adjustments necessary, which are of a normal and recurring nature, for the fair presentation of the Company’s financial position and of the results of operations and cash flows for the periods presented. The accompanying unaudited condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries.
	These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2014 included in the Company’s Annual Report on Form 10-K filed with the SEC. The results of operations for the interim period shown in this report are not necessarily indicative of the results that may be expected for any other interim period or for the full year. The balance sheet at December 31, 2014 has been derived from the audited financial statements at that date, but does not include all of the information and footnotes required by GAAP for complete financial statements.
Impact of Recently Issued Accounting Standards	Impact of Recently Issued Accounting Standards. In May 2014, the Financial Accounting Standards Board (FASB) amended the existing accounting standards for revenue recognition, which outlines a comprehensive revenue recognition model and supersedes most current revenue recognition guidance. The new standard requires a company to recognize revenue upon transfer of goods or services to a customer at an amount that reflects the expected consideration to be received in exchange for those goods or services. The amended guidance defines a five-step approach for recognizing revenue, which may require a company to use more judgment and make more estimates than under the current guidance. The amended guidance as currently issued will be effective for the Company starting in 2017. On April 1, 2015, the FASB voted to propose a one-year deferral to the effective date, but to permit entities to adopt one year earlier if they choose (i.e., the original effective date). The proposal will be subject to the FASB’s due process requirement, which includes a period for public comments. The new standard allows for two methods of adoption: (a) full retrospective adoption, meaning the standard is applied to all periods presented, or (b) modified retrospective adoption, meaning the cumulative effect of applying the new standard is recognized as an adjustment to the opening retained earnings balance. The Company is in the process of determining the adoption method as well as the effects the adoption will have on its consolidated financial statements.
Use of Estimates	Use of Estimates. The preparation of the condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and the accompanying notes. Actual results could differ from those estimates.
Revenue Recognition Policy	Revenue Recognition Policy. The Company recognizes revenue for the performance of services when each of the following four criteria is met: (i) persuasive evidence of an arrangement exists; (ii) services are rendered or products are delivered; (iii) the sales price is fixed or determinable; and (iv) collectability is reasonably assured.
	Effective in 2011, the Company follows 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 our 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 license fees; funding of research and/or development efforts; amounts due upon the achievement of specified milestones; manufacturing and royalties on future product sales.
	The ASC provides guidance relating to the separation of deliverables included in an arrangement into different units of accounting and the allocation of arrangement 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 payments when licensing its intellectual property, which often occurs in conjunction with a research and development agreement. The Company recognizes revenue attributed to the license upon delivery, provided that the license has stand-alone value.
	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. 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.

INVESTMENTS_Tables

INVESTMENTS (Tables)	3 Months Ended
	Mar. 31, 2015
Investments Schedule [Abstract]
Investments	Investments consist of the following (in thousands):
			March 31,		December 31,
			2015		2014
	Certificates of deposit		$	16,521	$	17,438
	Commercial paper			11,943		7,498
	Corporate debt securities			280,573		174,323
	Securities of government sponsored entities			6,160		1,028
	Total investments		$	315,197	$	200,287
Summary of Investments Classified as Available-For-Sale Securities	The following is a summary of investments classified as available-for-sale securities (in thousands):
			Contractual		Amortized			Gross		Gross			Aggregate
			Maturity		Cost			Unrealized		Unrealized			Estimated
			(in years)					Gains(1)		Losses(1)			Fair
													Value
	March 31, 2015:
	Classified as current assets:
	Certificates of deposit			Less than 1	$	9,320		$	2	$	(2	)	$	9,320
	Commercial paper			Less than 1		11,948			6		(11	)		11,943
	Corporate debt securities			Less than 1		178,406			14		(91	)		178,329
	Securities of government-sponsored entities			Less than 1		153			—		—			153
	Total short-term available-for-sale securities				$	199,827		$	22	$	(104	)	$	199,745
	Classified as non-current assets:
	Certificates of deposit			1 to 2	$	7,200		$	2	$	(1	)	$	7,201
	Corporate debt securities			1 to 2		102,345			14		(115	)		102,244
	Securities of government-sponsored entities			1 to 2		6,004			3		—			6,007
	Total long-term available-for-sale securities				$	115,549		$	19	$	(116	)	$	115,452
	December 31, 2014:
	Classified as current assets:
	Certificates of deposit			Less than 1	$	9,072		$	—	$	(6	)	$	9,066
	Commercial paper			Less than 1		7,497			1		—			7,498
	Corporate debt securities			Less than 1		145,321			5		(123	)		145,203
	Securities of government-sponsored entities			Less than 1		1,029			—		(1	)		1,028
	Total short-term available-for-sale securities				$	162,919		$	6	$	(130	)	$	162,795
	Classified as non-current assets:
	Certificates of deposit			1 to 2	$	8,400		$	—	$	(28	)	$	8,372
	Corporate debt securities			1 to 2		29,245			—		(125	)		29,120
	Total long-term available-for-sale securities				$	37,645		$	—	$	(153	)	$	37,492
	-1	Unrealized gains and losses are included in other comprehensive loss.
Available-For-Sale Investments in Unrealized Loss Position	The following table presents information about available-for-sale investments in an unrealized loss position (in thousands):
			Less Than 12 Months					12 Months or Greater					Total
			Estimated		Unrealized			Estimated		Unrealized			Estimated		Unrealized
			Fair		Losses			Fair		Losses			Fair		Losses
			Value					Value					Value
	March 31, 2015:
	Certificates of deposit		$	6,437	$	(3	)	$	240	$	—		$	6,677	$	(3	)
	Commercial paper			4,974		(11	)		—		—			4,974		(11	)
	Corporate debt securities			204,039		(192	)		6,371		(14	)		210,410		(206	)
	Total		$	215,450	$	(206	)	$	6,611	$	(14	)	$	222,061	$	(220	)
	December 31, 2014:
	Certificates of deposit		$	16,957	$	(34	)	$	—	$	—		$	16,957	$	(34	)
	Corporate debt securities			149,477		(248	)		—		—			149,477		(248	)
	Securities of government-sponsored entities			1,028		(1	)		—		—			1,028		(1	)
	Total		$	167,462	$	(283	)	$	—	$	—		$	167,462	$	(283	)

FAIR_VALUE_MEASUREMENTS_Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2015
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 March 31, 2015 and December 31, 2014 were determined using the inputs described above and are as follows (in millions):
					Fair Value Measurements Using
		Carrying			Quoted Prices  in			Significant Other			Significant
		Value			Active			Observable			Unobservable
					Markets for			Inputs			Inputs
					Identical Assets			(Level 2)			(Level 3)
					(Level 1)
	March 31, 2015:
	Classified as current assets:
	Cash and money market funds	$	136.4		$	136.4		$	—		$	—
	Certificates of deposit		9.3			9.3			—			—
	Commercial paper		17.4			—			17.4			—
	Securities of government-sponsored entities		0.2			—			0.2			—
	Corporate debt securities		206.7			—			206.7			—
	Subtotal		370			145.7			224.3			—
	Classified as long-term assets:
	Certificates of deposit		12.1			12.1			—			—
	Corporate debt securities		102.2			—			102.2			—
	Securities of government-sponsored entities		6			—			6			—
	Total		490.3			157.8			332.5			—
	Less cash, cash equivalents and restricted cash		(175.1	)		(141.2	)		(33.9	)		—
	Total investments	$	315.2		$	16.6		$	298.6		$	—
	December 31, 2014:
	Classified as current assets:
	Cash and money market funds	$	28.7		$	28.7		$	—		$	—
	Certificates of deposit		9.1			9.1			—			—
	Commercial paper		7.5			—			7.5			—
	Securities of government-sponsored entities		1.5			—			1.5			—
	Corporate debt securities		147			—			147			—
	Subtotal		193.8			37.8			156			—
	Classified as long-term assets:
	Certificates of deposit		13.2			13.2			—			—
	Corporate debt securities		29.1			—			29.1			—
	Total		236.1			51			185.1			—
	Less cash, cash equivalents and restricted cash		(35.8	)		(33.5	)		(2.3	)		—
	Total investments	$	200.3		$	17.5		$	182.8		$	—

SHAREBASED_COMPENSATION_Tables

SHARE-BASED COMPENSATION (Tables)	3 Months Ended
	Mar. 31, 2015
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
		March 31,
		2015			2014
	General and administrative	$	1.7		$	1.2
	Research and development		1.9			1.2
	Total share-based compensation expense	$	3.6		$	2.4
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
		March 31,
		2015		2014
	Risk-free interest rate	1.60%		2.30%
	Expected volatility of common stock	66.60%		71.30%
	Dividend yield	0.00%		0.00%
	Expected option term	6.7 years		7.1 years

REAL_ESTATE_Tables

REAL ESTATE (Tables)	3 Months Ended
	Mar. 31, 2015
Leases [Abstract]
Changes to Accrued Cease-Use Liability	The following table sets forth changes to the accrued cease-use liability during the three months ended March 31, 2015 and 2014 (in thousands):
		Three Months Ended
		March 31,
		2015			2014
	Beginning balance	$	2,678		$	3,096
	Payments		(113	)		(102	)
	Ending balance	$	2,565		$	2,994

Recovered_Sheet1

Revenue Recognition and Significant Collaborative Research and Development Agreements - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended
In Millions, unless otherwise specified	Jun. 30, 2010	Mar. 31, 2015
Mitsubishi Tanabe
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative agreement upfront payment received		$30
Collaborative agreement maximum additional payment to receive		85
Patent rights period		The longer of ten years or the life of the related patent rights.
Clinical trial cost		12
Collaborative arrangement right description		Under the terms of the Companybs agreement with Mitsubishi Tanabe, the collaboration effort between the parties to advance NBI-98854 towards commercialization 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 milestones will be achieved or when royalty payments will begin. Mitsubishi Tanabe may terminate the collaboration at its discretion upon 180 daysb written notice to the Company.
Collaboration termination notice period		180 days
Revenues recognized under collaboration agreement		19.8
Recognized up-front license fees		10.2
AbbVie
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative agreement upfront payment received	75
Patent rights period		Ten years or the life of the related patent rights.
Collaborative arrangement right description		The Company received funding for certain internal collaboration expenses, which included reimbursement from AbbVie for internal and external expenses related to the GnRH Compounds, through the end of 2012. 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
Amount remains outstanding under collaboration agreement		500
AbbVie | Development and regulatory event based payments
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative agreement maximum additional payment to receive	480
AbbVie | Commercial event based payments
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative agreement maximum additional payment to receive	$50

Investments_Detail

Investments (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Investments [Line Items]
Investments	$315,197	$200,287
Certificates of deposit
Schedule of Investments [Line Items]
Investments	16,521	17,438
Commercial paper
Schedule of Investments [Line Items]
Investments	11,943	7,498
Corporate debt securities
Schedule of Investments [Line Items]
Investments	280,573	174,323
Securities of government sponsored entities
Schedule of Investments [Line Items]
Investments	$6,160	$1,028

Summary_of_Investments_Classif

Summary of Investments Classified as Available-For-Sale Securities (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Aggregate Estimated Fair Value	315,197		200,287
Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Aggregate Estimated Fair Value	16,521		17,438
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Aggregate Estimated Fair Value	11,943		7,498
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Aggregate Estimated Fair Value	280,573		174,323
Securities of government sponsored entities
Schedule of Available-for-sale Securities [Line Items]
Aggregate Estimated Fair Value	6,160		1,028
Short-term investments
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	199,827		162,919
Gross Unrealized Gains	22	[1]	6	[1]
Gross Unrealized Losses	-104	[1]	-130	[1]
Aggregate Estimated Fair Value	199,745		162,795
Short-term investments | Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	9,320		9,072
Gross Unrealized Gains	2	[1]	0	[1]
Gross Unrealized Losses	-2	[1]	-6	[1]
Aggregate Estimated Fair Value	9,320		9,066
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	11,948		7,497
Gross Unrealized Gains	6	[1]	1	[1]
Gross Unrealized Losses	-11	[1]	0	[1]
Aggregate Estimated Fair Value	11,943		7,498
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	178,406		145,321
Gross Unrealized Gains	14	[1]	5	[1]
Gross Unrealized Losses	-91	[1]	-123	[1]
Aggregate Estimated Fair Value	178,329		145,203
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 | Securities of government sponsored entities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	153		1,029
Gross Unrealized Gains	0	[1]	0	[1]
Gross Unrealized Losses	0	[1]	-1	[1]
Aggregate Estimated Fair Value	153		1,028
Short-term investments | Securities of government sponsored entities | 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	115,549		37,645
Gross Unrealized Gains	19	[1]	0	[1]
Gross Unrealized Losses	-116	[1]	-153	[1]
Aggregate Estimated Fair Value	115,452		37,492
Long-term investments | Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,200		8,400
Gross Unrealized Gains	2	[1]	0	[1]
Gross Unrealized Losses	-1	[1]	-28	[1]
Aggregate Estimated Fair Value	7,201		8,372
Long-term investments | Certificates of deposit | Minimum
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities contractual maturity	1 year		1 year
Long-term investments | Certificates of deposit | Maximum
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities contractual maturity	2 years		2 years
Long-term investments | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	102,345		29,245
Gross Unrealized Gains	14	[1]	0	[1]
Gross Unrealized Losses	-115	[1]	-125	[1]
Aggregate Estimated Fair Value	102,244		29,120
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 | Securities of government sponsored entities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,004
Gross Unrealized Gains	3	[1]
Gross Unrealized Losses	0	[1]
Aggregate Estimated Fair Value	6,007
Long-term investments | Securities of government sponsored entities | Minimum
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities contractual maturity	1 year
Long-term investments | Securities of government sponsored entities | Maximum
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities contractual maturity	2 years
[1]	(1) Unrealized gains and losses are included in other comprehensive loss.

AvailableForSale_Investments_i

Available-For-Sale Investments in Unrealized Loss Position (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value	$215,450	$167,462
Less Than 12 Months, Unrealized Losses	-206	-283
12 Months or Greater, Estimated Fair Value	6,611	0
12 Months or Greater, Unrealized Losses	-14	0
Total Estimated Fair Value	222,061	167,462
Total Unrealized Losses	-220	-283
Certificates of deposit
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value	6,437	16,957
Less Than 12 Months, Unrealized Losses	-3	-34
12 Months or Greater, Estimated Fair Value	240	0
12 Months or Greater, Unrealized Losses	0	0
Total Estimated Fair Value	6,677	16,957
Total Unrealized Losses	-3	-34
Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value	4,974
Less Than 12 Months, Unrealized Losses	-11
12 Months or Greater, Estimated Fair Value	0
12 Months or Greater, Unrealized Losses	0
Total Estimated Fair Value	4,974
Total Unrealized Losses	-11
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value	204,039	149,477
Less Than 12 Months, Unrealized Losses	-192	-248
12 Months or Greater, Estimated Fair Value	6,371	0
12 Months or Greater, Unrealized Losses	-14	0
Total Estimated Fair Value	210,410	149,477
Total Unrealized Losses	-206	-248
Securities of government sponsored entities
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Estimated Fair Value		1,028
Less Than 12 Months, Unrealized Losses		-1
12 Months or Greater, Estimated Fair Value		0
12 Months or Greater, Unrealized Losses		0
Total Estimated Fair Value		1,028
Total Unrealized Losses		($1)

Assets_Measured_at_Fair_Value_

Assets Measured at Fair Value on Recurring Basis (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Millions, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	$315.20	$200.30
Investments Including Cash Equivalents And Restricted Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	490.3	236.1
Cash and Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	175.1	35.8
Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	370	193.8
Short-term investments | Cash and money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	136.4	28.7
Short-term investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	9.3	9.1
Short-term investments | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	17.4	7.5
Short-term investments | Securities of government-sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	0.2	1.5
Short-term investments | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	206.7	147
Long-term investments | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	12.1	13.2
Long-term investments | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	102.2	29.1
Long-term investments | Securities of government sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Value	6
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	16.6	17.5
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	157.8	51
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	141.2	33.5
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	145.7	37.8
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments | Cash and money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	136.4	28.7
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	9.3	9.1
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 | Securities of government-sponsored entities
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	12.1	13.2
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) | Long-term investments | Securities of government sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0
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	298.6	182.8
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	332.5	185.1
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	33.9	2.3
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	224.3	156
Significant Other Observable Inputs (Level 2) | Short-term investments | Cash and money market funds
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	17.4	7.5
Significant Other Observable Inputs (Level 2) | Short-term investments | Securities of government-sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0.2	1.5
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	206.7	147
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 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	102.2	29.1
Significant Other Observable Inputs (Level 2) | Long-term investments | Securities of government sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	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) | 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
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 funds
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 | Securities of government-sponsored entities
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 | 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 | Securities of government sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	$0

Compensation_Expense_Related_t

Compensation Expense Related to Share-Based Compensation (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	$3,600,000	$2,400,000
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	1,700,000	1,200,000
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	$1,900,000	$1,200,000

ShareBased_Compensation_Additi

Share-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option exercised	700,000	400,000
Cash received from stock option exercises	$2,800,000	$3,000,000
Common stock issued pursuant to the vesting of restricted stock units (RSUs)	200,000	100,000
Stock options granted	700,000	800,000
Share-based compensation expense	3,600,000	2,400,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	26,300,000
Unrecognized compensation cost, weighted average period of recognition	3 years 2 months 12 days
Stock vesting period	4 years
Share-based compensation expense	2,400,000	1,900,000
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	19,400,000
Unrecognized compensation cost, weighted average period of recognition	3 years 4 months 24 days
Stock vesting period	4 years
Share-based compensation expense	1,200,000	500,000
Restricted stock units granted	400,000
Restricted Stock Units (RSUs) | Performance Based Vesting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost	11,000,000
RSU with performance-based vesting requirements outstanding	500,000
Stock vesting period	5 years	5 years
Share-based compensation expense	$0
Restricted stock units granted	50,000	475,000

WeightedAverage_Assumptions_fo

Weighted-Average Assumptions for Stock Option Grants using Black-Scholes Option-Pricing Model (Detail) (Stock Options)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.60%	2.30%
Expected volatility of common stock	66.60%	71.30%
Dividend yield	0.00%	0.00%
Expected option term	6 years 8 months 12 days	7 years 1 month 6 days

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	1 Months Ended		3 Months Ended
	Feb. 28, 2015	Feb. 28, 2014	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2012
Class of Stock [Line Items]
Proceeds from common stock issuance	$270,700,000	$133,200,000	$273,525,000	$136,241,000
Common Stock
Class of Stock [Line Items]
Common stock issued	8,000,000	8,000,000
Common stock, offering price	$36	$17.75
February 2014 Shelf Registration
Class of Stock [Line Items]
Common stock issued			16,000,000
December 2012 Shelf Registration
Class of Stock [Line Items]
Common stock issued			0
December 2012 Shelf Registration | Maximum
Class of Stock [Line Items]
Aggregate initial offering price of common stock					$150,000,000

Real_Estate_Additional_Informa

Real Estate - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended		1 Months Ended
	Dec. 31, 2007	Mar. 31, 2015	Mar. 31, 2014	Sep. 30, 2012	Aug. 31, 2012	Dec. 31, 2010	Dec. 31, 2012	Nov. 30, 2012	Sep. 30, 2011	Dec. 31, 2008
	Building	RenewalOptions			sqft	sqft		sqft	sqft
						RenewalOptions		RenewalOptions	RenewalOptions
Real Estate Properties [Line Items]
Sale of facility and associated real property	$109,000,000
Mortgage debt retired	47,700,000
Cash received net of transaction costs and debt retirement	61,000,000
Leaseback transaction lease period	12 years
Number of building leased	2
Net deferred gain on real estate sale		16,800,000								39,100,000
Deferred gain recognized on real estate sale		800,000	800,000
Lease expiration year		2019
Percentage of management fee included in the base annual rent		3.50%
Letter of credit		4,600,000
Lease extension period		10 years
Number of times to renew the lease contract		2
Sublease
Real Estate Properties [Line Items]
Number of times to renew the lease contract						2
Subleased area					17,000	16,000
Rental income from sublease agreement						600,000
Sublease agreement period						3 years
Lease renewal additional periods						1 year
Cease-use expense				150,000		2,500,000
Deferred rent reversed				15,000		173,000
Third Sublease
Real Estate Properties [Line Items]
Number of times to renew the lease contract								2
Subleased area								14,000
Rental income from sublease agreement								500,000
Sublease agreement period								3 years 6 months
Lease renewal additional periods								1 year
Cease-use expense								1,200,000
Deferred rent reversed							250,000
Second Sublease
Real Estate Properties [Line Items]
Number of times to renew the lease contract									1
Subleased area									3,300
Rental income from sublease agreement									100,000
Sublease agreement period									3 years
Lease renewal additional periods									1 year
Cease-use expense									300,000
Deferred rent reversed									$47,000
Lease renewal extended additional periods									1 year

Changes_to_Accrued_CeaseUse_Li

Changes to Accrued Cease-Use Liability (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Beginning balance	$2,678	$3,096
Payments	-113	-102
Ending balance	$2,565	$2,994

Loss_Per_Common_Share_Addition

Loss Per Common Share - Additional Information (Detail) (USD $)	3 Months Ended
In Thousands, except Share data in Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Net loss	($1,192)	($11,842)
Potentially dilutive securities	3.9	3
Shares of common stock excluded from computation of diluted earnings per share outstanding	0.1	0.9