Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]
Balance at Dec. 31, 2018	$ 268,491	$ 13	$ 177,683	$ 90,795
Balance, shares at Dec. 31, 2018		13,126
Issuance of shares of common stock under restricted stock award agreements, shares		70
Forfeiture of shares of common stock under restricted stock award agreements, shares		(4)
Stock-based compensation	5,766		5,766
Shares issued for exercise of stock options	3,153		3,153
Shares issued for exercise of stock options, shares		125
Shares issued in secondary and public offering, net of offering costs	172,945	$ 2	172,943
Shares issued in secondary and public offering, net of offering costs, shares		2,300
Net income	25,237			25,237
Balance at Dec. 31, 2019	475,592	$ 15	359,545	116,032
Balance, shares at Dec. 31, 2019		15,617
Issuance of shares of common stock under restricted stock award agreements, shares		88
Forfeiture of shares of common stock under restricted stock award agreements, shares		(6)
Stock-based compensation	6,005		6,005
Shares issued for exercise of stock options	3,946	$ 1	3,945
Shares issued for exercise of stock options, shares		127
Net income	33,133			33,133
Balance at Dec. 31, 2020	518,676	$ 16	369,495	149,165
Balance, shares at Dec. 31, 2020		15,826
Issuance of shares of common stock under restricted stock award agreements, shares		89
Forfeiture of shares of common stock under restricted stock award agreements, shares		(7)
Stock-based compensation	9,434		9,434
Shares issued for exercise of stock options	1,108		1,108
Shares issued for exercise of stock options, shares		32
Net income	45,126			45,126
Balance at Dec. 31, 2021	$ 574,344	$ 16	$ 380,037	$ 194,291
Balance, shares at Dec. 31, 2021		15,940