Quarterly Results (Unaudited) (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]
Total revenues, net	$ 16,101	$ 12,851	$ 18,408	$ 19,891	$ 17,935	$ 16,151	$ 17,138	$ 15,657	$ 67,251	$ 66,881	$ 44,250
Gross profit	5,863	2,538	8,037	10,934	9,162	8,014	9,556	7,955	27,372	34,687
Operating income (loss)	(4,943)	(8,039)	(1,782)	2,967	326	303	1,076	837	(11,797)	2,542	(3,192)
Net income (loss)	(6,121)	(8,982)	(919)	831	(5,431)	(2,703)	(2,901)	(950)	(15,191)	(11,985)	6,668
Net income (loss) attributable to common stockholders	$ (6,121)	$ (8,982)	$ (919)	$ 831	$ (5,431)	$ (2,703)	$ (2,901)	$ (950)	$ (15,191)	$ (11,985)	$ 6,668
Basic net income (loss) per share (in dollars per share)	$ (0.11)	$ (0.17)	$ (0.02)	$ 0.02	$ (0.11)	$ (0.05)	$ (0.05)	$ (0.02)	$ (0.28)	$ (0.23)	$ 0.13
Diluted net income (loss) per share (in dollars per share)	$ (0.11)	$ (0.17)	$ (0.02)	$ 0.02	$ (0.11)	$ (0.05)	$ (0.05)	$ (0.02)	$ (0.28)	$ (0.23)	$ (0.07)