Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues:
Total revenues	$ 158	$ 214
Operating expenses:
Research and development	1,505	1,396
Selling, general and administrative	2,812	2,621
Total operating expenses	4,376	4,053
Loss from operations	(4,218)	(3,839)
Other income, net	120	38
Initial loss on common stock warrant and common stock adjustment feature liabilities		(4,000)
Change in fair value of common stock warrant and common stock adjustment feature liabilities	(8,495)	(1,900)
Offering costs		(904)
Net loss before income taxes	(12,593)	(10,605)
Income tax provision	(19)	(10)
Net loss	$ (12,612)	$ (10,615)
Net loss per share:
Basic and diluted	$ (2.64)	$ (4.86)
Weighted-average number of shares used in per share calculations:
Basic and diluted	4,776,540	2,186,196
Other comprehensive loss, net of tax
Unrealized losses on available-for-sale securities		$ 1
Other comprehensive loss		1
Comprehensive loss	$ (12,612)	(10,614)
Product
Revenues:
Total revenues	107	61
Operating expenses:
Cost of product revenues	59	36
Contract Research And Government Grants
Revenues:
Total revenues	$ 51	$ 153