CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings (Accumulated Deficit)
Beginning balance (in shares) at Dec. 31, 2016		976,000	30,860,000
Beginning balance, amount at Dec. 31, 2016	$ 26,223	$ 1	$ 31	$ 49,625	$ (23,434)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of Series B convertible preferred to common stock (in shares)		(976,000)	1,951,000
Conversion of Series B convertible preferred to common stock	0	$ (1)	$ 2	(1)
Stock based compensation	$ 871			871
Shares issued on net settlement of stock options (in shares)	19,688		47,000
Shares issued on net settlement of warrants (in shares)			20,000
Net income (loss)	$ (5,062)				(5,062)
Ending balance (in shares) at Dec. 31, 2017		0	32,878,000
Ending balance, amount at Dec. 31, 2017	22,032	$ 0	$ 33	50,495	(28,496)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	67,262
Ending balance, amount at Sep. 30, 2018	90,597
Beginning balance (in shares) at Dec. 31, 2017		0	32,878,000
Beginning balance, amount at Dec. 31, 2017	22,032	$ 0	$ 33	50,495	(28,496)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Options exercised for cash (in shares)			88,000
Options exercised for cash	202			202
Stock based compensation	$ 2,224			2,224
Shares issued on net settlement of stock options (in shares)	17,289		721,000
Shares issued on net settlement of stock options	$ 0		$ 1	(1)
Shares issued on net settlement of warrants (in shares)			18,000
Net income (loss)	62,719				62,719
Ending balance (in shares) at Dec. 31, 2018		0	33,705,000
Ending balance, amount at Dec. 31, 2018	87,177	$ 0	$ 34	52,920	34,223
Ending balance, amount at Mar. 31, 2019	82,831
Beginning balance (in shares) at Dec. 31, 2018		0	33,705,000
Beginning balance, amount at Dec. 31, 2018	87,177	$ 0	$ 34	52,920	34,223
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Options exercised for cash (in shares)			61,000
Options exercised for cash	207			207
Stock based compensation	3,581			3,581
Shares issued on net settlement of stock options (in shares)			223,000
Vested restricted stock issued (in shares)			181,000
Net income (loss)	(19,706)				(19,706)
Ending balance (in shares) at Dec. 31, 2019		0	34,170,000
Ending balance, amount at Dec. 31, 2019	$ 71,259	$ 0	$ 34	$ 56,708	$ 14,517