Organization and Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2022
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.
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, 2021, included in our Annual Report on Form 10-K, or the 2021 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, 2021, 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.
Recently Adopted and Issued Accounting Pronouncements	Recently Adopted Accounting Pronouncements.ASU 2020-06. In August 2020, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or 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 removed the separation models for convertible instruments with cash or beneficial conversion features. Instead, entities now account for convertible debt instruments wholly as debt, unless certain other conditions are met. The adoption of ASU 2020-06 prospectively reduces reported interest expense and increases (decreases) reported net income (loss), and resulted in a reclassification of certain conversion feature balance sheet amounts from stockholders’ equity to liabilities as it relates to the 2.25% fixed-rate convertible senior notes due May 15, 2024, or the 2024 Notes. We adopted ASU 2020-06 on January 1, 2022, using the modified retrospective transition method, which allowed for a cumulative-effect adjustment in the period of adoption and did not require restatement of prior period amounts. Under this transition method, the cumulative effect of the accounting change increased the carrying amount of the 2024 Notes by $42.2 million, reduced deferred tax liabilities by $9.9 million, reduced additional paid-in capital by $106.8 million and reduced the accumulated deficit by $74.5 million.
Fair Value Measurements	We record cash equivalents, debt securities available-for-sale and equity security investments 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 holding period restrictions longer than one year 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. We deem transfers between levels of the fair value hierarchy to have occurred at the end of the reporting period during which the event or change in circumstances that caused the transfer occurred.