Stock-based Compensation - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Number Of Options
Outstanding at December 31, 2017 (in shares)	13,180,950
Options granted (in shares)	0
Options exercised (in shares)	(1,198,732.00)
Options forfeited or canceled (in shares)	(161,194.00)
Outstanding at March 31, 2018 (in shares)	11,821,024	13,180,950
Options exercisable at March 31, 2018 (in shares)	8,101,710
Weighted- Average Exercise Price
Outstanding at December 31, 2017 (in dollars per share)	$ 6.30
Options granted (in dollars per share)	0.00
Options exercised (in dollars per share)	5.01
Options forfeited or canceled (in dollars per share)	9.05
Outstanding at March 31, 2018 (in dollars per share)	6.39	$ 6.30
Options exercisable at March 31, 2018 (in dollars per share)	$ 5.18
Stock Option Activity, Additional Disclosures
Weighted average remaining contractual life outstanding	6 years 9 months 18 days	7 years 7 days
Weighted average remaining contractual life exercisable	6 years 1 month 2 days
Options outstanding, Aggregate intrinsic value	$ 194,319	$ 329,786
Options exercised, Aggregate intrinsic value	21,365
Options exercisable, Aggregate intrinsic value	$ 143,034