Quarterly Results (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 Financial Information Disclosure [Abstract]
Total revenues, net	$ 17,935	$ 16,151	$ 17,138	$ 15,657	$ 13,071	$ 11,615	$ 8,893	$ 10,671	$ 66,881	$ 44,250	$ 33,740
Gross profit	9,162	8,014	9,556	7,955	5,944	6,077	3,666	5,628	34,687	21,315
Operating income (loss)	326	303	1,076	837	(2,769)	391	(1,911)	1,098	2,542	(3,192)	3,906
Net income (loss)	(5,431)	(2,703)	(2,901)	(950)	(6,375)	(2,888)	9,376	6,555	(11,985)	6,668	5,251
Net income (loss) attributable to common stockholders	$ (5,431)	$ (2,703)	$ (2,901)	$ (950)	$ (6,375)	$ (2,888)	$ 9,376	$ 6,555	$ (11,985)	$ 6,668	$ 5,251
Basic net income (loss) per share (in dollars per share)	$ (0.11)	$ (0.05)	$ (0.05)	$ (0.02)	$ (0.12)	$ (0.05)	$ 0.18	$ 0.12	$ (0.23)	$ 0.13	$ 0.11
Diluted net income (loss) per share (in dollars per share)	$ (0.11)	$ (0.05)	$ (0.05)	$ (0.02)	$ (0.12)	$ (0.05)	$ (0.03)	$ 0.01	$ (0.23)	$ (0.07)	$ 0.09