Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Common stock and paid-in capital	Accumulated other comprehensive loss	Retained earnings (accumulated deficit)
Balance at Dec. 31, 2017		$ 47,472	$ (65)	$ 9,160
Issuance of common stock		9,883
Issuance of warrants and senior convertible notes
Share-based compensation expense		463
Proceeds from employee stock purchase plan		39
Unrealized gain (loss) on available-for-sale securities, net of tax			(38)
Foreign currency translation adjustment	$ (78)		(78)
Stock repurchased				(147)
Cash dividends, $0.07 per share				(583)
Net loss	(16,687)			(16,687)
Balance at Dec. 31, 2018	52,201	57,857	(181)	(5,475)
Impact on retained earnings for change in revenue recognition policy				2,782
Issuance of common stock
Issuance of warrants and senior convertible notes		440
Share-based compensation expense		217
Proceeds from employee stock purchase plan		23
Unrealized gain (loss) on available-for-sale securities, net of tax			68
Foreign currency translation adjustment	(63)		(63)
Stock repurchased
Cash dividends, $0.07 per share
Net loss	(8,408)			(8,408)
Balance at Dec. 31, 2019	$ 44,478	$ 58,537	$ (176)	(13,883)
Impact on retained earnings for change in revenue recognition policy