Selected Quarterly Financial Data (Unaudited) - Selected Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 96,051	$ 83,911	$ 80,589	$ 73,213	$ 73,105	$ 67,187	$ 65,106	$ 57,919	$ 333,764	$ 263,317	$ 186,095
Cost of revenue	32,324	29,134	29,660	25,504	26,525	24,313	23,636	18,014	116,622	92,488	62,037
Gross Profit	63,727	54,777	50,929	47,709	46,580	42,874	41,470	39,905	217,142	170,829	124,058
Income (loss) before income taxes and equity in losses of unconsolidated investees	3,906	1,239	(918)	(1,751)	(1,515)	(1,092)	(383)	2,121	2,476	(869)	4,024
(Benefit from) provision for income taxes	(5,904)	456	482	1,355	881	(12,998)	(3,396)	(170)	(3,611)	(15,683)	1,659
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	9,810	783	(1,400)	(3,106)	(2,396)	11,906	3,013	2,291	6,087	14,814	2,365
Equity in losses of unconsolidated investees	$ (727)	$ (545)	$ (158)	$ 0	$ 0	$ 0	$ 0	$ 0	$ (1,430)	$ 0	$ 0
Net income (loss) per share attributable to common stockholders—Basic (in dollars per share)	$ 0.27	$ 0.01	$ (0.05)	$ (0.10)	$ (0.08)	$ 0.39	$ 0.10	$ 0.08	$ 0.14	$ 0.49	$ 0.09
Net income (loss) per share attributable to common stockholders—Diluted (in dollars per share)	$ 0.25	$ 0.01	$ (0.05)	$ (0.10)	$ (0.08)	$ 0.35	$ 0.09	$ 0.07	$ 0.13	$ 0.44	$ 0.08
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Basic (in shares)	33,606,943	33,446,841	33,219,487	31,611,841	31,045,700	30,604,384	30,210,322	29,990,006	32,978,065	30,464,583	11,993,429
Weighted average shares used to compute net income (loss) per share attributable to common stockholders—Diluted (in shares)	35,833,621	35,664,272	33,219,487	31,611,841	31,045,700	33,755,383	33,308,193	33,023,495	35,319,103	33,478,078	14,219,650
Income before equity in losses of unconsolidated investees	$ 9,083	$ 238	$ (1,558)	$ (3,106)	$ (2,396)	$ 11,906	$ 3,013	$ 2,291	$ 4,657	$ 14,814	$ 2,365