Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Treasury stock	Additional paid-in capital	Accumulated deficit	Accumulated other comprehensive income (loss)
Balance at Dec. 31, 2019	$ 310,820	$ 8	$ (638)	$ 979,428	$ (666,809)	$ (1,169)
Balance (in shares) at Dec. 31, 2019		7,964
Compensation expense for issuance of stock options to employees	5,468			5,468
Compensation expense for issuance of restricted stock to employees	2,632			2,632
Compensation expense for issuance of restricted stock to employees (in shares)		27
Reclassification of derivative liability to equity, net of tax	14,053			14,053
Interest payment for convertible notes	6,202	$ 1		6,201
Interest payment for convertible notes (in shares)		1,485
Reverse stock split adjustment	8			8
Other comprehensive income (loss)	(1,634)					(1,634)
Net loss	(99,594)				(99,594)
Balance at Dec. 31, 2020	237,955	$ 9	(638)	1,007,790	(766,403)	(2,803)
Balance (in shares) at Dec. 31, 2020		9,476
Compensation expense for issuance of stock options to employees	1,635			1,635
Compensation expense for issuance of restricted stock to employees	1,295			1,295
Compensation expense for issuance of restricted stock to employees (in shares)		89
Interest payment for convertible notes	12,420	$ 4		12,416
Interest payment for convertible notes (in shares)		3,685
Other comprehensive income (loss)	1,786					1,786
Net loss	(103,954)				(103,954)
Balance at Dec. 31, 2021	$ 151,137	$ 13	$ (638)	$ 1,023,136	$ (870,357)	$ (1,017)
Balance (in shares) at Dec. 31, 2021		13,250