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Organization and Summary of Significant Accounting Policies - Additional Information (Detail) shares in Millions		12 Months Ended
	May 02, 2017 USD ($) shares	Dec. 31, 2017 USD ($) Subsidiary Agreement shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares
Organization And Summary Of Significant Accounting Policies [Line Items]
Number of subsidiary wholly-owned by company | Subsidiary		2
Investment income, net		$ 6,238,000	$ 2,838,000	$ 1,928,000
Convertible senior notes principal amount		$ 517,500,000
Number of collaboration agreements | Agreement		2
2.25% Convertible Senior Notes due 2024
Organization And Summary Of Significant Accounting Policies [Line Items]
Convertible senior notes		7 years
Fair value of convertible senior note as percentage of principal amount		128.00%
Common share equivalents excluded from computation of earnings per share | shares	6.8
Convertible senior notes principal amount	$ 517,500,000
Restricted Stock Units and Employee Options
Organization And Summary Of Significant Accounting Policies [Line Items]
Common share equivalents excluded from computation of earnings per share | shares		3.4	3.8	4.1
Stock Options
Organization And Summary Of Significant Accounting Policies [Line Items]
Common share equivalents excluded from computation of earnings per share | shares		0.4	0.4	0.1
Ingrezza
Organization And Summary Of Significant Accounting Policies [Line Items]
Advertising costs		$ 10,100,000
Prepaid expenses, advertising costs		$ 0
Minimum
Organization And Summary Of Significant Accounting Policies [Line Items]
Average estimated useful life of equipment		3 years
Requisite service period of award		3 years
Maximum
Organization And Summary Of Significant Accounting Policies [Line Items]
Average estimated useful life of equipment		7 years
Requisite service period of award		4 years

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