Changes to Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Total
BALANCES (in shares) at Dec. 31, 2019	36,162				14
BALANCES at Dec. 31, 2019	$ 36	$ 334,299	$ (202,735)	$ (79)	$ (256)	$ 131,265
Exercise of options to purchase common stock (in shares)	44				0
Exercise of options to purchase common stock	$ 0	403	0	0	$ 0	403
Vesting of restricted stock units (in shares)	65				0
Vesting of restricted stock units	$ 0	(645)	0	0	$ 0	(645)
Share-based compensation expense	$ 0	2,242	0	0	$ 0	2,242
Shares issued in primary offering (in shares)	4,000				0
Shares issued in primary offering	$ 4	252,058	0	0	$ 0	252,062
Foreign Currency Translation	0	0	0	59	0	59
Net loss	$ 0	0	(3,590)	0	$ 0	(3,590)
BALANCES (in shares) at Mar. 31, 2020	40,271				14
BALANCES at Mar. 31, 2020	$ 40	588,357	(206,325)	(20)	$ (256)	381,796
BALANCES (in shares) at Dec. 31, 2020	40,732				14
BALANCES at Dec. 31, 2020	$ 41	600,388	(205,924)	(80)	$ (256)	394,169
Exercise of options to purchase common stock (in shares)	72				0
Exercise of options to purchase common stock	$ 0	714	0	0	$ 0	714
Vesting of restricted stock units (in shares)	23				0
Vesting of restricted stock units	$ 0	(1,529)	0	0	$ 0	(1,529)
Share-based compensation expense	$ 0	6,151	0	0	$ 0	6,151
Shares issued in primary offering (in shares)	2,415				0
Shares issued in primary offering	$ 2	332,518	0	0	$ 0	332,520
Foreign Currency Translation	0	0	0	259	0	259
Net loss	$ 0	0	(10,888)	0	$ 0	(10,888)
BALANCES (in shares) at Mar. 31, 2021	43,242				14
BALANCES at Mar. 31, 2021	$ 43	$ 938,242	$ (216,812)	$ 179	$ (256)	$ 721,396