Organization and Summary of Significant Accounting Policies - Net Loss per Share - Anti-dilutive (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Anti-Dilutive Securities
Anti-dilutive securities (in shares)	13,253,000	10,170,000	10,051,000
Share issuances under equity incentive plans and ESPP
Anti-Dilutive Securities
Anti-dilutive securities (in shares)	6,577,000	3,492,000	3,369,000
Restricted shares
Anti-Dilutive Securities
Anti-dilutive securities (in shares)		2,000	6,000
Share issuances upon the conversion of convertible senior notes
Anti-Dilutive Securities
Anti-dilutive securities (in shares)	6,676,000	6,676,000	6,676,000
Performance-based vesting
Anti-Dilutive Securities
Anti-dilutive securities (in shares)	414,000	978,750	1,305,000