Description of Operations and Summary of Significant Accounting Policies - Net loss per Share & Debt (Details) - USD ($) $ in Thousands			12 Months Ended
	Nov. 02, 2016	Jun. 02, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Anti-Dilutive Securities
Anti-dilutive securities (in shares)			10,418,000	4,739,000	3,899,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			10,418,000	4,739,000	3,899,000
Amortization of Debt Issuance Costs from Convertible Senior Notes due 2023
Net proceeds			$ 222,498	$ 0	$ 0
Net Loss per Share
Number of ordinary shares issued to Innoviva stockholders in connection with the Spin-Off transaction		32,260,105
Share issuances under equity incentive plan and ESPP
Anti-Dilutive Securities
Anti-dilutive securities (in shares)			3,709,000	4,537,000	3,475,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			3,709,000	4,537,000	3,475,000
Forfeitable shares
Anti-Dilutive Securities
Anti-dilutive securities (in shares)			33,000	202,000	424,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			33,000	202,000	424,000
Convertible subordinated notes
Anti-Dilutive Securities
Anti-dilutive securities (in shares)			6,676,000	0	0
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			6,676,000	0	0
Performance-based vesting
Anti-Dilutive Securities
Anti-dilutive securities (in shares)			1,440,000
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount			1,440,000
Convertible senior notes due 2023
Amortization of Debt Issuance Costs from Convertible Senior Notes due 2023
Aggregate principal amount	$ 230,000
Interest rate (as a percent)	3.25%
Net proceeds	$ 222,500
Transaction costs	$ 7,500