Net Income Per Share - Anti-Dilutive Securities (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive options and restricted stock not included in the calculation of diluted net income per share	7,672	7,677	88
Restricted stock subject to vesting
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive options and restricted stock not included in the calculation of diluted net income per share	26	31	88
Convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive options and restricted stock not included in the calculation of diluted net income per share	3,823	3,823	0
Warrants related to the issuance of convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive options and restricted stock not included in the calculation of diluted net income per share	3,823	3,823	0