Quarterly Results of Operations (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Results of Operations (unaudited)
Revenue	$ 70,458	$ 79,317	$ 78,437	$ 73,283	$ 62,530	$ 38,531	$ 41,150	$ 60,840	$ 301,495	$ 203,051	$ 195,632
Gross profit	21,973	29,179	27,174	23,380	18,796	15,144	14,484	21,740	101,706	70,164	67,935
Net income (loss)	$ 826	$ 6,101	$ 5,883	$ 1,868	$ 164	$ (4,704)	$ (6,900)	$ 174	$ 14,678	$ (11,266)	$ (17,144)
Net income (loss) per basic share (in dollars per share)	$ 0.01	$ 0.05	$ 0.05	$ 0.02	$ 0.00	$ (0.04)	$ (0.06)	$ 0.00	$ 0.13	$ (0.10)	$ (0.16)
Net income (loss) per diluted share (in dollars per share)	$ 0.01	$ 0.05	$ 0.05	$ 0.02	$ 0.00	$ (0.04)	$ (0.06)	$ 0.00	$ 0.12	$ (0.10)	$ (0.16)
Inventory reserves	$ 800	$ 300	$ 300		$ 800	$ 800	$ 200		$ 800	$ 800
Restructuring charges						$ 2,300	$ 100		$ 18	$ 2,621	$ 2,334
Variable compensation expense	800	$ 2,200
Stock-based compensation acceleration			1,100
Revenue for fully written down inventory	$ 1,500		$ 2,300