CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Revenue	$ 28,542	$ 34,111	$ 53,610	$ 65,838
Cost of revenue	14,882	15,940	28,188	30,899
Gross profit	13,660	18,171	25,422	34,939
Operating expenses:
Research and development	8,363	7,119	16,366	14,462
Sales and marketing	8,023	7,044	16,882	14,380
General and administrative	5,061	4,822	10,286	8,909
Restructuring costs	(178)		3,749
Total operating expenses	21,269	18,985	47,283	37,751
Loss from operations	(7,609)	(814)	(21,861)	(2,812)
Other income (expense), net	267	189	357	458
Interest expense	(351)	(307)	(580)	(681)
Loss before income taxes	(7,693)	(932)	(22,084)	(3,035)
Income tax expense	(39)	(45)	(90)	(102)
Net loss	$ (7,732)	$ (977)	$ (22,174)	$ (3,137)
Net loss per share — basic and diluted	$ (0.36)	$ (0.05)	$ (1.04)	$ (0.15)
Weighted-average shares outstanding — basic and diluted	21,333	20,636	21,229	20,491