Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenues	$ 8,432	$ 5,463
Cost of revenues	916	1,309
Gross profit	7,516	4,154
Operating expenses:
Selling and marketing	1,968	1,730
Research and development	2,682	2,255
General and administrative	2,700	2,190
Restructuring expense	104
Total operating expenses	7,454	6,175
Operating income (loss)	62	(2,021)
Other expense:
Interest expense, net		(171)
Change in fair value of warrant liability		(139)
Other expense	(10)	(40)
Income (loss) before provision for income taxes	52	(2,371)
Provision for income tax expense	4	10
Net income (loss)	$ 48	$ (2,381)
Net earnings (loss) per share:
Basic	$ 0.00	$ (0.16)
Diluted	$ 0.00	$ (0.16)
Weighted average shares outstanding:
Basic	31,297	15,299
Diluted	31,323	15,299
Preferred dividends per share	$ 25.00	$ 25.56