CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues, net	$ 11,728	$ 13,153	$ 37,652	$ 42,806
Cost of revenues	5,567	6,459	17,307	20,994
Gross profit	6,161	6,694	20,345	21,812
Operating expenses
Sales and marketing	3,732	5,296	12,453	18,831
Research and development	3,872	5,471	13,427	17,443
General and administrative	2,631	2,921	8,129	10,064
Impairment of goodwill	0	14,740	0	14,740
Total operating expenses	10,235	28,428	34,009	61,078
Loss from operations	(4,074)	(21,734)	(13,664)	(39,266)
Other income, net	640	336	1,712	1,008
Loss before (benefit from) provision for income taxes	(3,434)	(21,398)	(11,952)	(38,258)
(Benefit from) provision for income taxes	(161)	96	(70)	624
Net loss	(3,273)	(21,494)	(11,882)	(38,882)
Foreign currency translation adjustments	(54)	(93)	(49)	(227)
Comprehensive loss	$ (3,327)	$ (21,587)	$ (11,931)	$ (39,109)
Net loss per share available to common stockholders, basic and diluted (Note 11)	$ (0.49)	$ (3.71)	$ (1.90)	$ (6.75)
Weighted-average shares used to compute net loss per share available to common stockholders, basic and diluted	6,631	5,787	6,262	5,763
Stock-based compensation expense	$ 653	$ 875	$ 2,100	$ 2,933
Amortization of intangible assets	468	598	1,468	1,939
Cost of Revenues [Member]
Operating expenses
Stock-based compensation expense	127	160	394	536
Amortization of intangible assets	234	234	702	704
Restructuring related expenses	0	37	6	176
Sales and Marketing [Member]
Operating expenses
Stock-based compensation expense	155	181	540	692
Amortization of intangible assets	0	130	64	527
Restructuring related expenses	0	113	223	658
Research and Development [Member]
Operating expenses
Stock-based compensation expense	266	339	816	992
Amortization of intangible assets	234	234	702	705
Restructuring related expenses	0	0	0	115
General and Administrative [Member]
Operating expenses
Stock-based compensation expense	105	195	350	713
Amortization of intangible assets	0	0	0	3
Restructuring related expenses	$ 0	$ 11	$ 0	$ 158