Quarterly Results of Operations (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Results of Operations (Unaudited)
Revenue	$ 53,808	$ 41,281	$ 37,107	$ 34,565	$ 51,757	$ 41,624	$ 42,404	$ 38,052	$ 166,761	$ 173,837	$ 159,487
Gross profit	24,272	18,583	17,200	16,218	22,768	17,600	18,010	16,193	76,273	74,571	57,814
Net loss	$ (401)	$ (3,617)	$ (5,855)	$ (11,074)	$ (2,418)	$ (28,622)	$ (5,240)	$ (6,950)	$ (20,947)	$ (43,230)	$ (23,489)
Basic and diluted net loss per share (in dollars per share)	$ (0.01)	$ (0.07)	$ (0.11)	$ (0.21)	$ (0.05)	$ (0.55)	$ (0.10)	$ (0.14)	$ (0.40)	$ (0.84)	$ (0.46)
Basic and diluted weighted-average number of shares outstanding	51,644,295	52,473,601	52,633,054	52,372,857	52,186,221	51,875,785	51,445,613	51,217,220	52,279,738	51,684,397	50,637,541