Condensed Consolidated Statements of Stockholders' Deficit - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2018		16,185,146
Beginning balance at Dec. 31, 2018	$ (8,965)	$ 2	$ 296,688	$ (305,655)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of warrant liability to equity upon adoption of ASU 2017-11	86		86
Warrant exercised (in shares)		20,000
Warrant exercised	100		100
Stock compensation expense	1,024		1,024
Net loss	(2,921)			(2,921)
Ending balance (in shares) at Mar. 31, 2019		16,205,146
Ending balance at Mar. 31, 2019	$ (10,676)	$ 2	297,898	(308,576)
Beginning balance (in shares) at Dec. 31, 2019	16,616,165	16,616,165
Beginning balance at Dec. 31, 2019	$ (23,909)	$ 2	307,403	(331,314)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification of warrant liability to equity upon adoption of ASU 2017-11	0
Warrant exercised (in shares)		11,049
Warrant exercised	20		20
Stock option exercised (in shares)		223,643
Stock option exercised	1,759		1,759
Stock compensation expense (in shares)		25,724
Stock compensation expense	2,272		2,272
Net loss	$ (7,595)			(7,595)
Ending balance (in shares) at Mar. 31, 2020	16,876,581	16,876,581
Ending balance at Mar. 31, 2020	$ (27,453)	$ 2	$ 311,454	$ (338,909)