Neurocrine Biosciences (NBIX) 10-Q 1 Nov 21 2021 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2021	Oct. 27, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2021
Document Transition Report	false
Entity File Number	0-22705
Entity Registrant Name	NEUROCRINE BIOSCIENCES, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	33-0525145
Entity Address, Address Line One	12780 El Camino Real
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	92130
City Area Code	(858)
Local Phone Number	617-7600
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	NBIX
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		94,866,693
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Entity Central Index Key	0000914475
Current Fiscal Year End Date	--12-31

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 311.1	$ 187.1
Debt securities available-for-sale, at fair value (amortized cost $454.6 million at September 30, 2021 and $612.4 million at December 31, 2020)	454.8	613.9
Accounts receivable	163.8	157.1
Inventories	25.5	28
Other current assets	50.5	30.1
Total current assets	1,005.7	1,016.2
Deferred tax assets	310.4	319.4
Debt securities available-for-sale, at fair value (amortized cost $513.8 million at September 30, 2021 and $226.7 million at December 31, 2020)	513.7	227.1
Right-of-use assets	97.9	82.8
Equity securities	35.3	38.2
Property and equipment, net	51.1	44.6
Other assets	3.2	6.4
Total assets	2,017.3	1,734.7
Current liabilities:
Accounts payable and accrued liabilities	205.9	168.7
Other current liabilities	20	17.8
Total current liabilities	225.9	186.5
Convertible senior notes	330.7	317.9
Operating lease liabilities	106.4	94.4
Other long-term liabilities	8.3	9.7
Total liabilities	671.3	608.5
Stockholders’ equity:
Preferred stock, $0.001 par value; 5.0 shares authorized; no shares issued and outstanding at September 30, 2021 and December 31, 2020	0	0
Common stock, $0.001 par value; 220.0 shares authorized; issued and outstanding shares were 94.8 at September 30, 2021 and 93.5 at December 31, 2020	0.1	0.1
Additional paid-in capital	1,974	1,849.7
Accumulated other comprehensive income	0.4	1.8
Accumulated deficit	(628.5)	(725.4)
Total stockholders’ equity	1,346	1,126.2
Total liabilities and stockholders’ equity	$ 2,017.3	$ 1,734.7

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Amortized cost, current	$ 454.6	$ 612.4
Amortized cost, noncurrent	$ 513.8	$ 226.7
Preferred stock, par value (in USD per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	5	5
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in USD per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	220	220
Common stock, shares issued (in shares)	94.8	93.5
Common stock, shares outstanding (in shares)	94.8	93.5

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income (Loss) and Comprehensive Income (Loss) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues:
Revenues	$ 296	$ 258.5	$ 821.5	$ 798
Operating expenses:
Cost of sales	4.2	2.7	10.2	7.2
Research and development	92.7	69.1	240.7	208.3
Acquired in-process research and development	0	118.5	5	164.5
Selling, general and administrative	154.6	112.5	426.8	326.8
Total operating expenses	251.5	302.8	682.7	706.8
Operating income (loss)	44.5	(44.3)	138.8	91.2
Other (expense) income:
Interest expense	(6.6)	(8.5)	(19.2)	(25)
Unrealized loss on equity securities	(8.2)	(7)	(7.5)	(12.2)
Investment income and other, net	0.8	2.7	3.1	11
Total other expense, net	(14)	(12.8)	(23.6)	(26.2)
Income (loss) before provision for income taxes	30.5	(57.1)	115.2	65
Provision for income taxes	8	0.5	18.3	5.6
Net income (loss)	22.5	(57.6)	96.9	59.4
Unrealized (loss) gain on debt securities available-for-sale, net of tax	(0.3)	(1.4)	(1.4)	1.8
Comprehensive income (loss)	$ 22.2	$ (59)	$ 95.5	$ 61.2
Net income (loss) per share, basic (in USD per share)	$ 0.24	$ (0.62)	$ 1.03	$ 0.64
Net income (loss) per share, diluted (in USD per share)	$ 0.23	$ (0.62)	$ 0.99	$ 0.61
Weighted average common shares outstanding, basic (in shares)	94.7	93.3	94.5	93
Weighted average common shares outstanding, diluted (in shares)	97.7	93.3	97.9	98
Net product sales
Revenues:
Revenues	$ 288.8	$ 254.1	$ 786.6	$ 752.8
Collaboration revenues
Revenues:
Revenues	$ 7.2	$ 4.4	$ 34.9	$ 45.2

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance (in shares) at Dec. 31, 2019		92.3
Beginning Balance at Dec. 31, 2019	$ 636.9	$ 0.1	$ 1,768.1	$ 1.4	$ (1,132.7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	59.4				59.4
Unrealized gain (loss) on debt securities available-for-sale, net of tax	1.8			1.8
Share-based compensation expense	79		79
Issuances of common stock under stock plans (in shares)		1.1
Issuances of common stock under stock plans	27.2		27.2
Ending Balance (in shares) at Sep. 30, 2020		93.4
Ending Balance at Sep. 30, 2020	804.3	$ 0.1	1,874.3	3.2	(1,073.3)
Beginning Balance (in shares) at Jun. 30, 2020		93.2
Beginning Balance at Jun. 30, 2020	831.2	$ 0.1	1,842.2	4.6	(1,015.7)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(57.6)				(57.6)
Unrealized gain (loss) on debt securities available-for-sale, net of tax	(1.4)			(1.4)
Share-based compensation expense	26.7		26.7
Issuances of common stock under stock plans (in shares)		0.2
Issuances of common stock under stock plans	5.4		5.4
Ending Balance (in shares) at Sep. 30, 2020		93.4
Ending Balance at Sep. 30, 2020	804.3	$ 0.1	1,874.3	3.2	(1,073.3)
Beginning Balance (in shares) at Dec. 31, 2020		93.5
Beginning Balance at Dec. 31, 2020	1,126.2	$ 0.1	1,849.7	1.8	(725.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	96.9				96.9
Unrealized gain (loss) on debt securities available-for-sale, net of tax	(1.4)			(1.4)
Share-based compensation expense	98.6		98.6
Issuances of common stock under stock plans (in shares)		1.3
Issuances of common stock under stock plans	25.7		25.7
Ending Balance (in shares) at Sep. 30, 2021		94.8
Ending Balance at Sep. 30, 2021	1,346	$ 0.1	1,974	0.4	(628.5)
Beginning Balance (in shares) at Jun. 30, 2021		94.6
Beginning Balance at Jun. 30, 2021	1,279.2	$ 0.1	1,929.4	0.7	(651)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	22.5				22.5
Unrealized gain (loss) on debt securities available-for-sale, net of tax	(0.3)			(0.3)
Share-based compensation expense	37.1		37.1
Issuances of common stock under stock plans (in shares)		0.2
Issuances of common stock under stock plans	7.5		7.5
Ending Balance (in shares) at Sep. 30, 2021		94.8
Ending Balance at Sep. 30, 2021	$ 1,346	$ 0.1	$ 1,974	$ 0.4	$ (628.5)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash Flows from Operating Activities:
Net income	$ 96.9	$ 59.4
Reconciliation of net income to net cash provided by operating activities:
Share-based compensation expense	98.6	79
Depreciation	7.9	6.4
Amortization of debt discount	12.1	15.2
Amortization of debt issuance costs	0.8	1
Change in fair value of equity security investments	7.5	12.2
Deferred income taxes	9	0
Other	7.7	1.7
Change in operating assets and liabilities:
Accounts receivable	(6.7)	(30.3)
Inventories	2.5	(3.4)
Accounts payable and accrued liabilities	37.7	28.1
Other assets and liabilities, net	(21.7)	(35.3)
Net cash provided by operating activities	252.3	134
Cash Flows from Investing Activities:
Purchases of debt securities available-for-sale	(658.7)	(399.2)
Sales and maturities of debt securities available-for-sale	523.9	557.4
Purchases of equity securities	(4.6)	0
Purchases of property and equipment	(14.5)	(6.4)
Net cash (used in) provided by investing activities	(153.9)	151.8
Cash Flows from Financing Activities:
Issuances of common stock under benefit plans	25.7	27.2
Partial repurchase of convertible senior notes	(0.1)	0
Net cash provided by financing activities	25.6	27.2
Change in cash, cash equivalents and restricted cash	124	313
Cash, cash equivalents and restricted cash at beginning of period	190.3	115.5
Cash, cash equivalents and restricted cash at end of period	314.3	428.5
Supplemental Disclosure:
Non-cash capital expenditures	0.3	1.1
Right-of-use assets acquired through operating leases	21.6	0
Cash paid for interest	4.3	5.8
Cash paid for income taxes	$ 3.4	$ 0.4

Organization and Significant Ac

Organization and Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Organization and Significant Accounting Policies	Organization and Significant Accounting Policies Description of Business . Neurocrine Biosciences, Inc., or Neurocrine Biosciences, the Company, we, our or us, was incorporated in California in 1992 and reincorporated in Delaware in 1996. Neurocrine Continental, Inc., is a Delaware corporation and a wholly owned subsidiary of Neurocrine Biosciences. We also have two wholly owned Irish subsidiaries, Neurocrine Therapeutics, Ltd. and Neurocrine Europe, Ltd., both of which were formed in December 2014 and are inactive. We are a neuroscience-focused, biopharmaceutical company dedicated to discovering, developing and delivering life-changing treatments for people with serious, challenging and under-addressed neurological, endocrine and psychiatric disorders. Our diverse portfolio includes United States Food and Drug Administration, or FDA, approved treatments for tardive dyskinesia, Parkinson’s disease, endometriosis*, uterine fibroids* and clinical programs in multiple therapeutic areas. For nearly three decades, we have specialized in targeting and interrupting disease-causing mechanisms involving the interconnected pathways of the nervous and endocrine systems. (*in collaboration with AbbVie Inc.) Basis of Presentation . The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States, or GAAP, for interim financial information and with the instructions of the Securities and Exchange Commission, or 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 our 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 Neurocrine Biosciences and our wholly owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2020, included in our Annual Report on Form 10-K, or the 2020 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 the full year. The condensed consolidated balance sheet as of December 31, 2020, has been derived from the audited financial statements as of that date, but does not include all of the information and footnotes required by GAAP for complete financial statements. There were no significant changes to our significant accounting policies as disclosed in the 2020 Form 10-K. Recently Adopted Accounting Pronouncements. ASU 2019-12 . On January 1, 2021, we adopted Accounting Standards Update, or ASU, 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , using the modified retrospective transition method. ASU 2019-12 simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and amends existing guidance to improve consistent application of Topic 740. The adoption of ASU 2019-12 did not result in a cumulative-effect adjustment to retained earnings. The comparative prior period information continues to be reported under the accounting standards in effect during those periods. The impact of the adoption is expected to be immaterial to our financial position, results of operations, and cash flows on an ongoing basis. Recently Issued Accounting Pronouncements. ASU 2020-06 . In August 2020, the FASB issued ASU 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity's Own Equity , which simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts in an entity's own equity. Among other changes, ASU 2020-06 removes the separation models for convertible instruments with cash or beneficial conversion features. Instead, entities will account for convertible debt instruments wholly as debt, unless certain other conditions are met. The adoption of ASU 2020-06 is expected to prospectively reduce reported interest expense and increase reported net income, and result in a reclassification of certain conversion feature balance sheet amounts from stockholders’ equity to liabilities as it relates to the 2.25% convertible senior notes due May 15, 2024, or the 2024 Notes. Additionally, ASU 2020-06 requires the application of the if-converted method to calculate the impact of convertible instruments on diluted earnings per

Significant Collaboration and L

Significant Collaboration and Licensing Agreements	9 Months Ended
	Sep. 30, 2021
Business Combinations [Abstract]
Significant Collaboration and Licensing Agreements	Significant Collaboration and Licensing Agreements Takeda Pharmaceutical Company Limited, or Takeda. We entered into an exclusive license agreement with Takeda, which became effective in July 2020, to develop and commercialize certain compounds in Takeda’s early to mid-stage psychiatry pipeline. Specifically, Takeda granted us an exclusive license to (i) luvadaxistat (NBI-1065844/TAK-831) which we are studying in cognitive impairment associated with schizophrenia, (ii) NBI-1065845 (TAK-653) which we are studying in inadequate response to treatment in major depressive disorder, (iii) NBI-1065846 (TAK-041) which we are studying in anhedonia in depression and (iv) four non-clinical stage assets. Under the terms of the agreement, Takeda may be entitled to receive potential future payments of up to $1.9 billion upon the achievement of certain milestones associated with luvadaxistat and the four non-clinical stage assets, as well as receive royalties on the future net sales of such assets. With respect to luvadaxistat, Takeda declined to opt-in to a profit-sharing arrangement and instead will be entitled to receive royalties on the future net sales of such asset (in lieu of equally sharing in the operating profits and losses). With respect to NBI-1065845 and NBI-1065846, Takeda will retain the rights to opt-out of the profit-sharing arrangements pursuant to which Takeda would be entitled to receive royalties on the future net sales of such asset (in lieu of equally sharing in the operating profits and losses). Takeda may elect to exercise such opt-out rights immediately following the completion of the associated second Phase II clinical study or, under certain circumstances related to the development and commercialization activities to be performed by us, before the initiation of a Phase III clinical study for such asset. We and Takeda will equally share in the operating profits and losses associated with NBI-1065845 and NBI-1065846. Idorsia Pharmaceuticals Ltd., or Idorsia. In May 2020, we entered a collaboration and licensing agreement with Idorsia to license the global rights to NBI-827104 (ACT-709478), a potent, selective, orally active and brain penetrating T-type calcium channel blocker, in clinical development for the treatment of a rare pediatric epilepsy. Under the terms of the agreement, Idorsia may be entitled to receive potential future payments of up to $1.7 billion upon the achievement of certain milestones as well as receive royalties on the future net sales of any collaboration product. Xenon Pharmaceuticals Inc., or Xenon. In December 2019, we entered into a license and collaboration agreement with Xenon to identify, research, and develop sodium channel inhibitors, including clinical candidate NBI-921352 (XEN901) and three preclinical candidates. Under the terms of the agreement, Xenon may be entitled to receive potential future payments of up to $1.7 billion upon the achievement of certain milestones as well as receive royalties on the future net sales of any collaboration product. In September 2021, we received approval of a clinical trial application, or CTA, submitted in the European Union for NBI-921352 for the treatment of focal-onset seizures in adults. In connection with the approval of the CTA for NBI-921352, we paid Xenon a regulatory milestone of $10.0 million, of which we expensed $4.5 million as research and development in the third quarter of 2021, and purchased 0.3 million shares of Xenon’s common stock (at $19.9755 per share) for $5.5 million. The purchased shares were recorded at a fair value of $4.6 million after considering Xenon’s stock price on the measurement date and certain transfer restrictions applicable to the shares. Further, we recorded a charge of $0.9 million to research and development to reflect the premium paid on our purchase of the shares on the measurement date. Voyager Therapeutics, Inc., or Voyager. We entered into a collaboration and license agreement with Voyager, which became effective in March 2019, to develop and commercialize four programs using Voyager’s proprietary gene therapy platform. The four programs consist of the NBIb-1817 (VY-AADC) for Parkinson’s disease program, the Friedreich’s ataxia program and the rights to two undisclosed programs. In February 2021, we notified Voyager of our termination of the NBIb-1817 for Parkinson’s disease program, which became effective August 2, 2021. The termination does not apply to any other development program other than NBIb-1817 for Parkinson’s disease, and our collaboration and license agreement with Voyager will otherwise continue in effect. Under the terms of the agreement, Voyager may be entitled to receive potential future payments of up to $1.3 billion upon the achievement of certain milestones, as well as receive royalties on the future net sales of any collaboration product. BIAL – Portela & Ca, S.A., or BIAL. In February 2017, we entered into an exclusive license agreement with BIAL to acquire the United States, or US, and Canada rights to ONGENTYS ® (opicapone). Under the terms of the agreement, BIAL may be entitled to receive potential future payments of up to $75.0 million upon the achievement of certain milestones. We launched ONGENTYS in the US in September 2020, after receiving FDA approval for ONGENTYS as an adjunctive therapy to levodopa/DOPA decarboxylase inhibitors in adult Parkinson's disease patients in April 2020. Mitsubishi Tanabe Pharma Corporation, or MTPC. In March 2015, we entered into a collaboration and license agreement with MTPC for the development and commercialization of INGREZZA ® (valbenazine) for movement disorders in Japan and other select Asian markets. Under the terms of the agreement, we are entitled to receive royalties on the future worldwide net sales of any collaboration product in select territories in Asia and may also be entitled to receive potential future payments of up to $55.0 million upon the achievement of certain milestones. In April 2021, MTPC submitted a marketing authorization application, or MAA, with the Ministry of Health and Welfare in Japan for valbenazine for the treatment of tardive dyskinesia. The MTPC submission of the MAA for valbenazine triggered a milestone payment of $15.0 million, which we recognized as milestone revenue in the second quarter of 2021. We are currently conducting the KINECT-HD study, a placebo-controlled Phase III study of valbenazine in adult Huntington disease patients with chorea. In connection with our performance of the study, we recognized non-cash collaboration revenue of $0.9 million and $3.3 million, respectively, in the three and nine months ended September 30, 2021, and $0.5 million and $1.8 million, respectively, in the three and nine months ended September 30, 2020. As of September 30, 2021, $3.5 million of revenue is being deferred in connection with our continuing performance obligations under the collaboration and will be recognized as non-cash collaboration revenue over the remaining study period using an input method according to costs incurred to-date relative to estimated total costs associated with the study. AbbVie Inc., or AbbVie. In June 2010, we entered into an exclusive worldwide collaboration with AbbVie to develop and commercialize elagolix and all next-generation gonadotropin-releasing factor antagonists for women’s and men’s health. Under the terms of the agreement, we are entitled to receive royalties on the future worldwide net sales of any collaboration product and may also be entitled to receive potential future payments of up to $366.0 million upon the achievement of certain milestones. AbbVie launched ORILISSA ® (elagolix tablets) in the US and Canada in August and November 2018, respectively. In June 2020, AbbVie launched ORIAHNN ® (elagolix, estradiol and norethindrone acetate capsules and elagolix capsules) in the US. We receive royalties at tiered percentage rates on AbbVie net sales of elagolix. We recognized elagolix royalty revenue of $5.9 million and $16.3 million, respectively, in the three and nine months ended September 30, 2021, and $3.9 million and $13.4 million, respectively, in the three and nine months ended September 30, 2020.

Debt Securities

Debt Securities	9 Months Ended
	Sep. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Debt Securities	Debt Securities The following table summarizes the amortized cost, unrealized gain and loss recognized in accumulated other comprehensive income (loss), and fair value of debt securities available-for-sale, aggregated by major security type and contractual maturity. September 30, December 31, (in millions) Contractual Amortized Unrealized Gain Unrealized Loss Fair Amortized Unrealized Gain Unrealized Loss Fair Commercial paper 0 to 1 years $ 208.6 $ — $ — $ 208.6 $ 82.2 $ — $ — $ 82.2 Corporate debt securities 0 to 1 years 170.6 0.2 — 170.8 299.3 1.4 — 300.7 Securities of government-sponsored entities 0 to 1 years 75.4 — — 75.4 230.9 0.1 — 231.0 $ 454.6 $ 0.2 $ — $ 454.8 $ 612.4 $ 1.5 $ — $ 613.9 Corporate debt securities 1 to 2 years $ 328.6 $ 0.2 $ (0.3) $ 328.5 $ 144.8 $ 0.4 $ — $ 145.2 Securities of government-sponsored entities 1 to 2 years 185.2 0.1 (0.1) 185.2 81.9 0.1 (0.1) 81.9 $ 513.8 $ 0.3 $ (0.4) $ 513.7 $ 226.7 $ 0.5 $ (0.1) $ 227.1 As of September 30, 2021, our security portfolio consisted of 160 securities related to investments in debt securities available-for-sale, of which 82 securities were in an unrealized loss position. Our investments in corporate debt securities in an unrealized loss position as of September 30, 2021 are of high credit quality (rated A or higher). Unrealized losses on these investments were primarily due to changes in interest rates. We do not intend to sell these investments and it is not more likely than not that we will be required to sell these investments before recovery of their amortized cost basis. We did not recognize an allowance for credit losses as of September 30, 2021 or December 31, 2020. The following table summarizes debt securities available-for-sale in an unrealized loss position for less than 12 months, aggregated by major security type. There were no debt securities available-for-sale in an unrealized loss position for longer than 12 months as of September 30, 2021 or December 31, 2020. September 30, December 31, (in millions) Fair Unrealized Fair Unrealized Corporate Debt Securities $ 298.5 $ (0.3) $ — $ — Securities of government-sponsored entities 107.3 (0.1) 95.0 (0.1) $ 405.8 $ (0.4) $ 95.0 $ (0.1) Accrued interest receivables on debt securities available-for-sale totaled $2.8 million and $3.7 million as of September 30, 2021 and December 31, 2020, respectively. We do not measure an allowance for credit losses for accrued interest receivables. For the purposes of identifying and measuring an impairment, accrued interest is excluded from both the fair value and amortized cost basis of the debt security. Uncollectible accrued interest receivables associated with an impaired debt security are reversed against interest income upon identification of the impairment. No accrued interest receivables were written off during the nine months ended September 30, 2021 or 2020.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements We record cash equivalents and investments in debt securities available-for-sale and equity securities at fair value based on a fair value hierarchy that distinguishes between assumptions based on market data (observable inputs) and our own assumptions (unobservable inputs). The fair value hierarchy consists of the following three levels: Level 1 – Quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 – Quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability. Level 3 – Unobservable inputs that reflect our own assumptions about the assumptions that market participants would use in pricing the asset or liability when there is little, if any, market activity for the asset or liability at the measurement date. Investments in debt securities available-for-sale are classified as Level 2 and carried at fair value. We estimate the fair value of debt securities available-for-sale by utilizing third-party pricing services. These pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. Such inputs include market pricing based on real-time trade data for similar instruments, issuer credit spreads, benchmark yields, broker/dealer quotes and other observable inputs. We validate valuations obtained from third-party pricing services by understanding the models used, obtaining market values from other pricing sources, and analyzing data in certain instances. Investments in equity securities of certain companies that are subject to certain holding period restrictions are classified as Level 3 and carried at fair value using an option pricing valuation model. The most significant assumptions within the option pricing valuation model are the stock price volatility, which is based on the historical volatility of similar companies, and the discount for lack of marketability related to the term of the restrictions. The carrying amounts of accounts receivable and accounts payable and accrued liabilities approximate their fair values due to their short-term maturities. Investments, which were measured at fair value on a recurring basis, consisted of the following: September 30, December 31, Fair Fair Value Measurements Using Fair Fair Value Measurements Using (in millions) Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash and cash equivalents: Cash and money market funds $ 311.1 $ 311.1 $ — $ — $ 187.1 $ 187.1 $ — $ — Restricted cash: Certificates of deposit 3.2 3.2 — — 3.2 3.2 — — Debt securities available-for-sale: Commercial paper 208.6 — 208.6 — 82.2 — 82.2 — Corporate debt securities 499.3 — 499.3 — 445.9 — 445.9 — Securities of government-sponsored entities 260.6 — 260.6 — 312.9 — 312.9 — Equity securities: Equity securities–biotechnology industry 35.3 — — 35.3 38.2 — — 38.2 $ 1,318.1 $ 314.3 $ 968.5 $ 35.3 $ 1,069.5 $ 190.3 $ 841.0 $ 38.2 The following table presents a reconciliation of equity security investments, which were measured at fair value on a recurring basis using significant unobservable inputs (Level 3): Three Months Ended Nine Months Ended (in millions) 2021 2020 2021 2020 Balance at beginning of period $ 38.9 $ 50.7 $ 38.2 $ 55.9 Purchases (1) 4.6 — 4.6 — Unrealized loss included in earnings (8.2) (7.0) (7.5) (12.2) Balance at end of period $ 35.3 $ 43.7 $ 35.3 $ 43.7 _________________________ (1) In September 2021, we purchased 0.3 million shares of Xenon's common stock, valued at $4.6 million on the date of purchase, in connection with the approval of the CTA for NBI-921352. As of September 30, 2021, the discount for lack of marketability used in the valuation analysis of equity security investments ranged from 2.5% to 7.5% (weighted average of 3.9%). The discount for lack of marketability was weighted by the relative fair value of the instruments. A significant increase (decrease) in the discount for lack of marketability in isolation would result in a significantly lower (higher) fair value measurement. Unrealized gains and losses on equity security investments are included in other income (expense), net.

Inventories

Inventories	9 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consisted of the following: (in millions) September 30, December 31, Raw materials $ 13.0 $ 16.6 Work in process 1.3 2.4 Finished goods 11.2 9.0 Total inventories $ 25.5 $ 28.0

Cash, Cash Equivalents and Rest

Cash, Cash Equivalents and Restricted Cash	9 Months Ended
	Sep. 30, 2021
Restricted Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Restricted Cash	Cash, Cash Equivalents and Restricted Cash The following table presents a reconciliation of cash, cash equivalents and restricted cash to amounts shown in the condensed consolidated statements of cash flows. (in millions) September 30, September 30, Cash and cash equivalents $ 311.1 $ 425.3 Restricted cash included in other assets 3.2 3.2 Total cash, cash equivalents and restricted cash $ 314.3 $ 428.5

Leases

Leases	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Leases	Leases We have operating leases for our office and laboratory facilities, including our corporate headquarters, with terms that expire from 2024 through 2031. Certain of these lease agreements contain clauses for renewal at our option. As we were not reasonably certain to exercise any of these renewal options at commencement of the associated leases, no such options were recognized as part of our operating lease right-of-use, or ROU, assets or operating lease liabilities. In connection with our operating leases, in lieu of a cash security deposits, Wells Fargo Bank, N.A., issued letters of credit on our behalf, which are secured by deposits totaling $3.2 million. The following table presents supplemental operating lease information. Nine Months Ended (in millions, except weighted average data) 2021 2020 Operating lease cost $ 11.2 $ 7.4 Cash paid for amounts included in the measurement of operating lease liabilities $ 9.1 $ 6.4 September 30, September 30, Weighted average remaining lease term 9.0 years 10.5 years Weighted average discount rate 5.3 % 5.8 % The following table presents approximate future minimum lease payments under operating leases. (in millions) September 30, Year ending December 31, 2021 (3 months remaining) $ 3.5 Year ending December 31, 2022 16.8 Year ending December 31, 2023 17.5 Year ending December 31, 2024 17.0 Year ending December 31, 2025 15.5 Thereafter 85.4 Total operating lease payments 155.7 Less accreted interest 33.8 Total operating lease liabilities 121.9 Less current operating lease liabilities included in other current liabilities 15.5 Noncurrent operating lease liabilities $ 106.4

Convertible Senior Notes

Convertible Senior Notes	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Convertible Senior Notes	Convertible Senior Notes On May 2, 2017, we completed a private placement of $517.5 million in aggregate principal amount of the 2024 Notes and entered into an indenture agreement, or the 2024 Indenture, with respect to the 2024 Notes. In November 2020, we entered into separate, privately negotiated transactions with certain holders of the 2024 Notes to repurchase $136.2 million aggregate principal amount of the 2024 Notes for an aggregate repurchase price of $186.9 million in cash. At September 30, 2021, $381.2 million aggregate principal amount of the 2024 Notes remained outstanding. Interest on the 2024 Notes is due semi-annually on May 15 and November 15 of each year. Pursuant to the terms of the 2024 notes, we could not redeem the 2024 Notes prior to May 15, 2021. On or after May 15, 2021, we may redeem for cash all or part of the 2024 Notes if the last reported sale price (as defined in the 2024 Indenture) of our common stock has been at least 130% of the conversion price then in effect (equal to $98.70 as of September 30, 2021) for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading-day period ending on, and including, the trading day immediately before the date which we provide notice of redemption. 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 (and only during such calendar quarter), if the last reported sale price of our 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 (equal to $98.70 as of September 30, 2021) on each applicable trading day; (ii) during the five five (iii) upon the occurrence of specified corporate events, including a merger or a sale of all or substantially all of our assets; or (iv) if we call 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 our common stock or a combination of cash and shares of our common stock, at our option. It is our 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 observation period as described in the 2024 Indenture. The conversion value is the sum of the daily conversion value which is the product of the effective conversion rate divided by 25 days and the daily volume weighted average price, or VWAP, of our common stock. The “share amount” is the cumulative “daily share amount” during the observation period, which is calculated by dividing the daily VWAP into the difference between the daily conversion value (i.e., conversion rate x daily VWAP) and $1,000. 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 our common stock. At the initial conversion rate, settlement of the 2024 Notes for shares of our common stock would approximate 5.0 million shares. 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 represented a premium of approximately 42.5% to the closing sale price of $53.28 per share of our common stock on the Nasdaq Global Select Market on April 26, 2017, the date that we 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, we would be required to repay the $381.2 million in principal value and any conversion premium in any combination of cash and shares of our common stock, at our option. If we undergo a fundamental change, as defined in the 2024 Indenture, subject to certain conditions, holders of the 2024 Notes may require us 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, we 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 our general unsecured obligations that rank senior in right of payment to all of our indebtedness that is expressly subordinated in right of payment to the 2024 Notes, and equal in right of payment to our unsecured indebtedness. While the 2024 Notes are currently classified as a long-term liability, the future convertibility and associated balance sheet classification will be monitored at each quarterly reporting date and analyzed dependent upon market prices of our common stock during the prescribed measurement periods. In the event that we have the election to redeem the 2024 Notes or 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. We are required to separately account for the liability and equity components of the 2024 Notes as they may be settled entirely or partially in cash upon conversion in a manner that reflects our 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 was recorded in additional paid-in capital on the consolidated balance sheet at the issuance date. That equity component is treated as a discount on the liability component of the 2024 Notes, which is amortized over the seven-year term of the 2024 Notes using the effective interest rate method. The equity component is not re-measured as long as it continues to meet the conditions for equity classification. At September 30, 2021, the remaining period over which the discount on the liability component will be amortized was approximately 2.6 years. We 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 us. 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. The 2024 Notes, net of discounts and deferred financing costs, consisted of the following: (in millions) September 30, December 31, Principal $ 381.2 $ 381.3 Deferred financing costs (3.2) (4.0) Debt discount, net (47.3) (59.4) Net carrying amount $ 330.7 $ 317.9 The 2024 Notes were recorded at the estimated value of a similar non-convertible instrument on the date of issuance and accretes to the face value of the 2024 Notes over their seven-year term. The fair value of the 2024 Notes, which was estimated utilizing market quotations from an over-the-counter trading market (Level 2), was $497.7 million at September 30, 2021 and $514.3 million at December 31, 2020.

Net Income (Loss) Per Share

Net Income (Loss) Per Share	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	Net Income (Loss) Per Share Net income (loss) per share was calculated as follows: Three Months Ended Nine Months Ended (in millions, except per share data) 2021 2020 2021 2020 Net income (loss) - basic and diluted $ 22.5 $ (57.6) $ 96.9 $ 59.4 Weighted-average common shares outstanding: Basic 94.7 93.3 94.5 93.0 Effect of dilutive securities: Stock options 1.8 — 1.9 2.5 Restricted stock (1) 0.2 — 0.3 0.5 2024 Notes (2) 1.0 — 1.1 2.0 Diluted 97.7 93.3 97.9 98.0 Net income (loss) per share: Basic $ 0.24 $ (0.62) $ 1.03 $ 0.64 Diluted $ 0.23 $ (0.62) $ 0.99 $ 0.61 Shares excluded from diluted per share amounts because their effect would have been anti-dilutive 4.5 10.9 4.0 2.3 _________________________ (1) In August 2021, our board of directors approved an equity grant in the form of restricted stock units, or RSUs, to our full-time employees other than our executive officers, consisting of approximately 0.5 million RSUs, which will vest over a period of two years. (2) Convertible debt instruments that may be settled entirely or partly in cash (such as the 2024 Notes) may, in certain circumstances where the borrower has the ability and intent to settle in cash, be accounted for under the treasury stock method. We issued the 2024 Notes with a combination settlement feature, which we have the ability and intent to use upon conversion of the 2024 Notes, to settle the principal amount of debt for cash and the excess of the principal portion in shares of our common stock. As a result, of the approximately 5.0 million shares underlying the 2024 Notes, only the shares required to settle the excess of the principal portion are considered under the treasury stock method.

Legal Proceedings

Legal Proceedings	9 Months Ended
	Sep. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Legal Proceedings	Legal ProceedingsIn the second quarter of 2021, we received notices from (i) Teva Pharmaceuticals Development, Inc., (ii) Lupin Limited, (iii) Crystal Pharmaceutical (Suzhou) Co. Ltd., and (iv) Zydus Pharmaceuticals (USA) Inc. (each an “ANDA Filer”) that each company had filed an abbreviated new drug application, or ANDA, with the FDA seeking approval of a generic version of INGREZZA. The ANDAs each contained a Paragraph IV Patent Certification alleging that certain of our patents covering INGREZZA are invalid and/or will not be infringed by each ANDA Filer’s manufacture, use or sale of the medicine for which the ANDA was submitted. We filed suit in the U.S. District Court for the District of Delaware in July 2021 against (i) Teva Pharmaceuticals, Inc. and its affiliates Teva Pharmaceuticals Development, Inc., Teva Pharmaceuticals USA, Inc. and Teva Pharmaceutical Industries Ltd., (ii) Lupin Limited and its affiliates Lupin Pharmaceuticals, Inc., and Lupin Atlantis Holdings S.A., (iii) Crystal Pharmaceutical (Suzhou) Co., Ltd., and its affiliate Crystal Pharmatech Co., Ltd., and (iv) Zydus Pharmaceuticals (USA) Inc. and its affiliates Zydus Worldwide DMCC, Cadila Healthcare Limited d/b/a Zydus Cadila and Zydus Healthcare (USA) LLC. We also filed suit in the U.S. District Court for the District of New Jersey in July 2021 against Zydus Pharmaceuticals (USA) Inc. and its affiliates Zydus Worldwide DMCC, Cadila Healthcare Limited d/b/a Zydus Cadila and Zydus Healthcare (USA) LLC seeking to prevent any ANDA Filer from selling a generic version of INGREZZA.

Organization and Significant _2

Organization and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2021
Accounting Policies [Abstract]
Description of Business	Description of Business . Neurocrine Biosciences, Inc., or Neurocrine Biosciences, the Company, we, our or us, was incorporated in California in 1992 and reincorporated in Delaware in 1996. Neurocrine Continental, Inc., is a Delaware corporation and a wholly owned subsidiary of Neurocrine Biosciences. We also have two wholly owned Irish subsidiaries, Neurocrine Therapeutics, Ltd. and Neurocrine Europe, Ltd., both of which were formed in December 2014 and are inactive. We are a neuroscience-focused, biopharmaceutical company dedicated to discovering, developing and delivering life-changing treatments for people with serious, challenging and under-addressed neurological, endocrine and psychiatric disorders. Our diverse portfolio includes United States Food and Drug Administration, or FDA, approved treatments for tardive dyskinesia, Parkinson’s disease, endometriosis*, uterine fibroids* and clinical programs in multiple therapeutic areas. For nearly three decades, we have specialized in targeting and interrupting disease-causing mechanisms involving the interconnected pathways of the nervous and endocrine systems. (*in collaboration with AbbVie Inc.)
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, or GAAP, for interim financial information and with the instructions of the Securities and Exchange Commission, or 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 our 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 Neurocrine Biosciences and our wholly owned subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. These financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto for the year ended December 31, 2020, included in our Annual Report on Form 10-K, or the 2020 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 the full year. The condensed consolidated balance sheet as of December 31, 2020, has been derived from the audited financial statements as of that date, but does not include all of the information and footnotes required by GAAP for complete financial statements. There were no significant changes to our significant accounting policies as disclosed in the 2020 Form 10-K.
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements. ASU 2019-12 . On January 1, 2021, we adopted Accounting Standards Update, or ASU, 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes , using the modified retrospective transition method. ASU 2019-12 simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and amends existing guidance to improve consistent application of Topic 740. The adoption of ASU 2019-12 did not result in a cumulative-effect adjustment to retained earnings. The comparative prior period information continues to be reported under the accounting standards in effect during those periods. The impact of the adoption is expected to be immaterial to our financial position, results of operations, and cash flows on an ongoing basis. Recently Issued Accounting Pronouncements. ASU 2020-06 . In August 2020, the FASB issued ASU 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity's Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity's Own Equity , which simplifies the accounting for certain financial instruments with characteristics of liabilities and equity, including convertible instruments and contracts in an entity's own equity. Among other changes, ASU 2020-06 removes the separation models for convertible instruments with cash or beneficial conversion features. Instead, entities will account for convertible debt instruments wholly as debt, unless certain other conditions are met. The adoption of ASU 2020-06 is expected to prospectively reduce reported interest expense and increase reported net income, and result in a reclassification of certain conversion feature balance sheet amounts from stockholders’ equity to liabilities as it relates to the 2.25% convertible senior notes due May 15, 2024, or the 2024 Notes. Additionally, ASU 2020-06 requires the application of the if-converted method to calculate the impact of convertible instruments on diluted earnings per
Fair Value Measurements	We record cash equivalents and investments in debt securities available-for-sale and equity securities at fair value based on a fair value hierarchy that distinguishes between assumptions based on market data (observable inputs) and our own assumptions (unobservable inputs). The fair value hierarchy consists of the following three levels: Level 1 – Quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 – Quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active or inputs that are observable, either directly or indirectly, for substantially the full term of the asset or liability. Level 3 – Unobservable inputs that reflect our own assumptions about the assumptions that market participants would use in pricing the asset or liability when there is little, if any, market activity for the asset or liability at the measurement date. Investments in debt securities available-for-sale are classified as Level 2 and carried at fair value. We estimate the fair value of debt securities available-for-sale by utilizing third-party pricing services. These pricing services utilize industry standard valuation models, including both income and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. Such inputs include market pricing based on real-time trade data for similar instruments, issuer credit spreads, benchmark yields, broker/dealer quotes and other observable inputs. We validate valuations obtained from third-party pricing services by understanding the models used, obtaining market values from other pricing sources, and analyzing data in certain instances. Investments in equity securities of certain companies that are subject to certain holding period restrictions are classified as Level 3 and carried at fair value using an option pricing valuation model. The most significant assumptions within the option pricing valuation model are the stock price volatility, which is based on the historical volatility of similar companies, and the discount for lack of marketability related to the term of the restrictions. The carrying amounts of accounts receivable and accounts payable and accrued liabilities approximate their fair values due to their short-term maturities.

Debt Securities (Tables)

Debt Securities (Tables)	9 Months Ended
	Sep. 30, 2021
Investments, Debt and Equity Securities [Abstract]
Amortized Cost, Gross Unrealized Gains and Losses, Allowance for Credit Losses and Fair Value of Debt Securities Available-For-Sale	The following table summarizes the amortized cost, unrealized gain and loss recognized in accumulated other comprehensive income (loss), and fair value of debt securities available-for-sale, aggregated by major security type and contractual maturity. September 30, December 31, (in millions) Contractual Amortized Unrealized Gain Unrealized Loss Fair Amortized Unrealized Gain Unrealized Loss Fair Commercial paper 0 to 1 years $ 208.6 $ — $ — $ 208.6 $ 82.2 $ — $ — $ 82.2 Corporate debt securities 0 to 1 years 170.6 0.2 — 170.8 299.3 1.4 — 300.7 Securities of government-sponsored entities 0 to 1 years 75.4 — — 75.4 230.9 0.1 — 231.0 $ 454.6 $ 0.2 $ — $ 454.8 $ 612.4 $ 1.5 $ — $ 613.9 Corporate debt securities 1 to 2 years $ 328.6 $ 0.2 $ (0.3) $ 328.5 $ 144.8 $ 0.4 $ — $ 145.2 Securities of government-sponsored entities 1 to 2 years 185.2 0.1 (0.1) 185.2 81.9 0.1 (0.1) 81.9 $ 513.8 $ 0.3 $ (0.4) $ 513.7 $ 226.7 $ 0.5 $ (0.1) $ 227.1
Gross Unrealized Losses and Fair Value Available-For-Sale Investments in Unrealized Loss Position	The following table summarizes debt securities available-for-sale in an unrealized loss position for less than 12 months, aggregated by major security type. There were no debt securities available-for-sale in an unrealized loss position for longer than 12 months as of September 30, 2021 or December 31, 2020. September 30, December 31, (in millions) Fair Unrealized Fair Unrealized Corporate Debt Securities $ 298.5 $ (0.3) $ — $ — Securities of government-sponsored entities 107.3 (0.1) 95.0 (0.1) $ 405.8 $ (0.4) $ 95.0 $ (0.1)

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2021
Fair Value Disclosures [Abstract]
Investments Measured at Fair Value on Recurring Basis	Investments, which were measured at fair value on a recurring basis, consisted of the following: September 30, December 31, Fair Fair Value Measurements Using Fair Fair Value Measurements Using (in millions) Level 1 Level 2 Level 3 Level 1 Level 2 Level 3 Cash and cash equivalents: Cash and money market funds $ 311.1 $ 311.1 $ — $ — $ 187.1 $ 187.1 $ — $ — Restricted cash: Certificates of deposit 3.2 3.2 — — 3.2 3.2 — — Debt securities available-for-sale: Commercial paper 208.6 — 208.6 — 82.2 — 82.2 — Corporate debt securities 499.3 — 499.3 — 445.9 — 445.9 — Securities of government-sponsored entities 260.6 — 260.6 — 312.9 — 312.9 — Equity securities: Equity securities–biotechnology industry 35.3 — — 35.3 38.2 — — 38.2 $ 1,318.1 $ 314.3 $ 968.5 $ 35.3 $ 1,069.5 $ 190.3 $ 841.0 $ 38.2
Reconciliation of Our Investment in Restricted Equity Securities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Level 3)	The following table presents a reconciliation of equity security investments, which were measured at fair value on a recurring basis using significant unobservable inputs (Level 3): Three Months Ended Nine Months Ended (in millions) 2021 2020 2021 2020 Balance at beginning of period $ 38.9 $ 50.7 $ 38.2 $ 55.9 Purchases (1) 4.6 — 4.6 — Unrealized loss included in earnings (8.2) (7.0) (7.5) (12.2) Balance at end of period $ 35.3 $ 43.7 $ 35.3 $ 43.7 _________________________ (1) In September 2021, we purchased 0.3 million shares of Xenon's common stock, valued at $4.6 million on the date of purchase, in connection with the approval of the CTA for NBI-921352.

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2021
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories consisted of the following: (in millions) September 30, December 31, Raw materials $ 13.0 $ 16.6 Work in process 1.3 2.4 Finished goods 11.2 9.0 Total inventories $ 25.5 $ 28.0

Cash, Cash Equivalents and Re_2

Cash, Cash Equivalents and Restricted Cash (Tables)	9 Months Ended
	Sep. 30, 2021
Restricted Cash and Cash Equivalents [Abstract]
Summary of Reconciliation of Cash, Cash Equivalents, and Restricted Cash	The following table presents a reconciliation of cash, cash equivalents and restricted cash to amounts shown in the condensed consolidated statements of cash flows. (in millions) September 30, September 30, Cash and cash equivalents $ 311.1 $ 425.3 Restricted cash included in other assets 3.2 3.2 Total cash, cash equivalents and restricted cash $ 314.3 $ 428.5

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2021
Leases [Abstract]
Schedule of Description of Operating Lease	The following table presents supplemental operating lease information. Nine Months Ended (in millions, except weighted average data) 2021 2020 Operating lease cost $ 11.2 $ 7.4 Cash paid for amounts included in the measurement of operating lease liabilities $ 9.1 $ 6.4 September 30, September 30, Weighted average remaining lease term 9.0 years 10.5 years Weighted average discount rate 5.3 % 5.8 %
Lessee, Operating Lease, Liability, Maturity	The following table presents approximate future minimum lease payments under operating leases. (in millions) September 30, Year ending December 31, 2021 (3 months remaining) $ 3.5 Year ending December 31, 2022 16.8 Year ending December 31, 2023 17.5 Year ending December 31, 2024 17.0 Year ending December 31, 2025 15.5 Thereafter 85.4 Total operating lease payments 155.7 Less accreted interest 33.8 Total operating lease liabilities 121.9 Less current operating lease liabilities included in other current liabilities 15.5 Noncurrent operating lease liabilities $ 106.4

Convertible Senior Notes (Table

Convertible Senior Notes (Tables)	9 Months Ended
	Sep. 30, 2021
Debt Disclosure [Abstract]
Summary of Notes Net of Discount and Deferred Financing Costs	The 2024 Notes, net of discounts and deferred financing costs, consisted of the following: (in millions) September 30, December 31, Principal $ 381.2 $ 381.3 Deferred financing costs (3.2) (4.0) Debt discount, net (47.3) (59.4) Net carrying amount $ 330.7 $ 317.9

Net Income (Loss) Per Share (Ta

Net Income (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2021
Earnings Per Share [Abstract]
Schedule of Net Income (Loss) Per Share	Net income (loss) per share was calculated as follows: Three Months Ended Nine Months Ended (in millions, except per share data) 2021 2020 2021 2020 Net income (loss) - basic and diluted $ 22.5 $ (57.6) $ 96.9 $ 59.4 Weighted-average common shares outstanding: Basic 94.7 93.3 94.5 93.0 Effect of dilutive securities: Stock options 1.8 — 1.9 2.5 Restricted stock (1) 0.2 — 0.3 0.5 2024 Notes (2) 1.0 — 1.1 2.0 Diluted 97.7 93.3 97.9 98.0 Net income (loss) per share: Basic $ 0.24 $ (0.62) $ 1.03 $ 0.64 Diluted $ 0.23 $ (0.62) $ 0.99 $ 0.61 Shares excluded from diluted per share amounts because their effect would have been anti-dilutive 4.5 10.9 4.0 2.3 _________________________ (1) In August 2021, our board of directors approved an equity grant in the form of restricted stock units, or RSUs, to our full-time employees other than our executive officers, consisting of approximately 0.5 million RSUs, which will vest over a period of two years. (2) Convertible debt instruments that may be settled entirely or partly in cash (such as the 2024 Notes) may, in certain circumstances where the borrower has the ability and intent to settle in cash, be accounted for under the treasury stock method. We issued the 2024 Notes with a combination settlement feature, which we have the ability and intent to use upon conversion of the 2024 Notes, to settle the principal amount of debt for cash and the excess of the principal portion in shares of our common stock. As a result, of the approximately 5.0 million shares underlying the 2024 Notes, only the shares required to settle the excess of the principal portion are considered under the treasury stock method.

Organization and Significant _3

Organization and Significant Accounting Policies - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2021subsidiary
Accounting Policies [Abstract]
Number of wholly owned Irish subsidiaries	2

Significant Collaboration and_2

Significant Collaboration and Licensing Agreements - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	Sep. 08, 2021	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Purchases to acquire equity securities					$ 4.6	$ 0
Revenues		$ 296		$ 258.5	821.5	798
Collaborative Arrangement | Takeda
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments		1,900			1,900
Collaborative Arrangement | Idorsia
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments		1,700			1,700
Collaborative Arrangement | Xenon
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments		1,700			1,700
Milestone payment	$ 10
Research and development	$ 4.5
Number of shares owned (in shares)	300
Common stock per share (in USD per share)	$ 19.9755
Milestone purchase payment	$ 5.5
Purchases to acquire equity securities	4.6
Premium paid for equity purchase	$ 0.9
Collaborative Arrangement | Voyager
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments		1,300			1,300
Collaborative Arrangement | BIAL
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments		75			75
Collaborative Arrangement | MTPC
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue recognized		0.9		0.5	3.3	1.8
Collaborative Arrangement | License | MTPC
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payment receipts		55			55
Revenues			$ 15
Deferred revenue, balance		3.5			3.5
Collaborative Arrangement | Royalty | AbbVie
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payment receipts		366			366
Revenues		$ 5.9		$ 3.9	$ 16.3	$ 13.4

Debt Securities - Amortized Cos

Debt Securities - Amortized Cost, Gross Unrealized Gains and Losses, Allowance for Credit Losses and Fair Value of Debt Securities Available-For-Sale (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Short-term investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 454.6	$ 612.4
Unrealized Gain	0.2	1.5
Unrealized Loss	0	0
Fair Value	454.8	613.9
Short-term investments | Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	170.6	299.3
Unrealized Gain	0.2	1.4
Unrealized Loss	0	0
Fair Value	170.8	300.7
Short-term investments | Securities of government-sponsored entities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	75.4	230.9
Unrealized Gain	0	0.1
Unrealized Loss	0	0
Fair Value	75.4	231
Short-term investments | Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	208.6	82.2
Unrealized Gain	0	0
Unrealized Loss	0	0
Fair Value	208.6	82.2
Long-term investments
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	513.8	226.7
Unrealized Gain	0.3	0.5
Unrealized Loss	(0.4)	(0.1)
Fair Value	513.7	227.1
Long-term investments | Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	328.6	144.8
Unrealized Gain	0.2	0.4
Unrealized Loss	(0.3)	0
Fair Value	328.5	145.2
Long-term investments | Securities of government-sponsored entities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	185.2	81.9
Unrealized Gain	0.1	0.1
Unrealized Loss	(0.1)	(0.1)
Fair Value	$ 185.2	$ 81.9

Debt Securities - Additional In

Debt Securities - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2021USD ($)security	Sep. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Investments, Debt and Equity Securities [Abstract]
Number of debt securities available for sale | security	160
Number of debt securities available for sale in unrealized loss position | security	82
Accrued interest receivables | $	$ 2.8		$ 3.7
Accrued interest receivables write-off | $	$ 0	$ 0

Debt Securities - Gross Unreali

Debt Securities - Gross Unrealized Losses and Fair Value Available-For-Sale Investments in Unrealized Loss Position (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	$ 405.8	$ 95
Less Than 12 Months, Unrealized Loss	(0.4)	(0.1)
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	298.5	0
Less Than 12 Months, Unrealized Loss	(0.3)	0
Securities of government-sponsored entities
Debt Securities, Available-for-sale [Line Items]
Less Than 12 Months, Fair Value	107.3	95
Less Than 12 Months, Unrealized Loss	$ (0.1)	$ (0.1)

Fair Value Measurements - Inves

Fair Value Measurements - Investments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 1,318.1	$ 1,069.5
Level 1 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	314.3	190.3
Level 2 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	968.5	841
Level 3 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	35.3	38.2
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	499.3	445.9
Corporate debt securities | Level 1 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Corporate debt securities | Level 2 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	499.3	445.9
Corporate debt securities | Level 3 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Securities of government-sponsored entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	260.6	312.9
Securities of government-sponsored entities | Level 1 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Securities of government-sponsored entities | Level 2 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	260.6	312.9
Securities of government-sponsored entities | Level 3 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Equity securities–biotechnology industry
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	35.3	38.2
Equity securities–biotechnology industry | Level 1 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Equity securities–biotechnology industry | Level 2 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Equity securities–biotechnology industry | Level 3 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	35.3	38.2
Cash and money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	311.1	187.1
Cash and money market funds | Level 1 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	311.1	187.1
Cash and money market funds | Level 2 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Cash and money market funds | Level 3 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	3.2	3.2
Certificates of deposit | Level 1 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	3.2	3.2
Certificates of deposit | Level 2 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Certificates of deposit | Level 3 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	208.6	82.2
Commercial paper | Level 1 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	0	0
Commercial paper | Level 2 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	208.6	82.2
Commercial paper | Level 3 | Fair Value, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets on recurring basis	$ 0	$ 0

Fair Value Measurements - Recon

Fair Value Measurements - Reconciliation of Our Investment in Restricted Equity Securities Measured at Fair Value on Quarterly Basis Using Significant Unobservable Inputs (Level 3) (Detail) - USD ($) shares in Thousands, $ in Millions	Sep. 08, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Roll Forward]
Balance at beginning of period				$ 38.2
Purchases to acquire equity securities				4.6	$ 0
Unrealized loss included in earnings		$ (8.2)	$ (7)	(7.5)	(12.2)
Balance at end of period		35.3		35.3
Xenon | Collaborative Arrangement
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Roll Forward]
Purchases to acquire equity securities	$ 4.6
Number of shares owned (in shares)	300
Equity Securities | Level 3 | Fair Value, Recurring
Fair Value, Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Roll Forward]
Balance at beginning of period		38.9	50.7	38.2	55.9
Purchases to acquire equity securities		4.6	0	4.6	0
Unrealized loss included in earnings		(8.2)	(7)	(7.5)	(12.2)
Balance at end of period		$ 35.3	$ 43.7	$ 35.3	$ 43.7

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - Discount for Lack of Marketability	Sep. 30, 2021
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities measurement input	0.025
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities measurement input	0.075
Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity securities measurement input	0.039

Inventories - Summary of Invent

Inventories - Summary of Inventories (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Inventory Disclosure [Abstract]
Raw materials	$ 13	$ 16.6
Work in process	1.3	2.4
Finished goods	11.2	9
Total inventories	$ 25.5	$ 28

Cash, Cash Equivalents and Re_3

Cash, Cash Equivalents and Restricted Cash - Summary of Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Restricted Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 311.1	$ 187.1	$ 425.3
Restricted cash included in other assets	3.2		3.2
Total cash, cash equivalents and restricted cash	$ 314.3		$ 428.5

Leases - Narrative Information

Leases - Narrative Information (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Restricted cash	$ 3.2	$ 3.2

Leases - Supplemental Informati

Leases - Supplemental Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating lease cost	$ 11.2	$ 7.4
Cash paid for amounts included in the measurement of operating lease liabilities	$ 9.1	$ 6.4
Weighted average remaining lease term	9 years	10 years 6 months
Weighted average discount rate	5.30%	5.80%

Leases - Liability, Payment, Du

Leases - Liability, Payment, Due (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Leases [Abstract]
Year ending December 31, 2021 (3 months remaining)	$ 3.5
Year ending December 31, 2022	16.8
Year ending December 31, 2023	17.5
Year ending December 31, 2024	17
Year ending December 31, 2025	15.5
Thereafter	85.4
Total operating lease payments	155.7
Less accreted interest	33.8
Total operating lease liabilities	121.9
Less current operating lease liabilities included in other current liabilities	15.5
Noncurrent operating lease liabilities	$ 106.4	$ 94.4

Convertible Senior Notes - Addi

Convertible Senior Notes - Additional Information (Detail) $ / shares in Units, shares in Millions	May 02, 2017USD ($)d$ / shares	Nov. 30, 2020USD ($)	Sep. 30, 2021USD ($)shares	Sep. 30, 2021USD ($)$ / sharesshares	Dec. 31, 2020USD ($)
Debt Instrument [Line Items]
Principal amount			$ 381,200,000	$ 381,200,000	$ 381,300,000
2.25% Convertible Senior Notes due 2024
Debt Instrument [Line Items]
Principal amount	$ 517,500,000		$ 381,200,000	$ 381,200,000
Aggregate principal amount repurchased		$ 136,200,000
Aggregate repurchase price paid in cash		$ 186,900,000
Threshold percentage of common stock price trigger	130.00%
Common stock price trigger (in USD per share) | $ / shares				$ 98.70
Threshold common stock trading days | d	20
Threshold consecutive common stock trading days | d	30
Number of consecutive business days	5 days
Principal amount on conversion rate	$ 1,000
Minimum percentage of common stock price trigger	98.00%
Conversion observation period	25 days
Convertible senior notes convertible in to shares	0.0131711
Convertible senior notes conversion price (in USD per share) | $ / shares	$ 75.92
Shares issued to settle notes at initial conversion rate (in shares) | shares			5	5
Convertible senior note premium	42.50%
Market price of common stock (in USD per share) | $ / shares	$ 53.28
Convertible senior notes redemption rate	100.00%
Convertible senior note carrying value of the liability component	$ 368,300,000
Convertible senior note assumed borrowing rate	7.50%
Convertible senior note carrying value of the equity component	$ 149,200,000
Convertible senior notes term	7 years
Discount on liability component, remaining amortization period				2 years 7 months 6 days
Transaction cost related to issuance of convertible senior notes	$ 14,700,000
Debt instrument events of default percentage of principal and accrued and unpaid interest due and payable upon default	100.00%
Convertible senior notes fair value			$ 497,700,000	$ 497,700,000	$ 514,300,000

Convertible Senior Notes - Debt

Convertible Senior Notes - Debt Net of Discounts and Deferred Financing Costs (Detail) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Debt Disclosure [Abstract]
Principal	$ 381.2	$ 381.3
Deferred financing costs	(3.2)	(4)
Debt discount, net	(47.3)	(59.4)
Net carrying amount	$ 330.7	$ 317.9

Net Income (Loss) Per Share - S

Net Income (Loss) Per Share - Schedule of Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Subsidiary, Sale of Stock [Line Items]
Net income (loss) - basic and diluted	$ 22.5	$ (57.6)	$ 96.9	$ 59.4
Weighted-average common shares outstanding:
Basic (in shares)	94.7	93.3	94.5	93
Effect of dilutive securities:
Diluted (in shares)	97.7	93.3	97.9	98
Net income (loss) per share:
Basic (in USD per share)	$ 0.24	$ (0.62)	$ 1.03	$ 0.64
Diluted (in USD per share)	$ 0.23	$ (0.62)	$ 0.99	$ 0.61
Shares excluded from diluted per share amounts because their effect would have been anti-dilutive (in shares)	4.5	10.9	4	2.3
2.25% Convertible Senior Notes due 2024
Effect of dilutive securities:
2024 Notes (in shares)	1	0	1.1	2
Stock options
Effect of dilutive securities:
Effect of dilutive securities (in shares)	1.8	0	1.9	2.5
Restricted stock
Effect of dilutive securities:
Effect of dilutive securities (in shares)	0.2	0	0.3	0.5

Net Income (Loss) Per Share - A

Net Income (Loss) Per Share - Additional Information (Detail) - shares shares in Millions	1 Months Ended	3 Months Ended	9 Months Ended
	Aug. 31, 2021	Sep. 30, 2021	Sep. 30, 2021
Restricted stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of RSUs (in shares)	0.5
Vesting period	2 years
2.25% Convertible Senior Notes due 2024
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares issued to settle notes at initial conversion rate (in shares)		5	5