Consolidated Statement of Stockholders’ Equity - USD ($) $ in Thousands		Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Total
Cumulative effect of change in accounting principle				$ 768	$ 768
Balance		$ 1	$ 335,767	(126,471)	209,297
Balance at Mar. 31, 2018		$ 1	335,767	(127,239)	208,529
Balance, Shares at Mar. 31, 2018		14,487,650
Equity based compensation	[1]		8,936		8,936
Equity based compensation, Shares	[1]	68,082
Stock option exercises			2,564		2,564
Stock option exercises, Shares		125,976
Shares withheld for taxes			(139)		(139)
Shares withheld for taxes, Shares		(5,300)
Net loss				(32,432)	(32,432)
Balance at Dec. 31, 2018		$ 1	347,128	(158,903)	188,226
Balance, Shares at Dec. 31, 2018		14,676,408
Balance at Sep. 30, 2018		$ 1	343,930	(150,553)	193,378
Balance, Shares at Sep. 30, 2018		14,573,267
Equity based compensation	[1]		1,459		1,459
Equity based compensation, Shares	[1]	18,014
Stock option exercises			1,739		1,739
Stock option exercises, Shares		85,127
Net loss				(8,350)	(8,350)
Balance at Dec. 31, 2018		$ 1	347,128	(158,903)	188,226
Balance, Shares at Dec. 31, 2018		14,676,408
Cumulative effect of change in accounting principle			(188)	188
Balance		$ 1	349,039	(168,276)	180,764
Balance at Mar. 31, 2019		$ 1	349,227	(168,464)	180,764
Balance, Shares at Mar. 31, 2019		14,739,145
Issuance of stock during July 2019 follow-on offering, net of closing costs		$ 1	94,243		94,244
Issuance of stock during July 2019 follow-on offering, net of closing costs, Shares		2,222,223
Equity based compensation	[1]		4,393		4,393
Equity based compensation, Shares	[1]	93,956
Stock option exercises			2,220		2,220
Stock option exercises, Shares		102,323
Shares withheld for taxes			(467)		(467)
Shares withheld for taxes, Shares		(10,967)
Net loss				(25,900)	(25,900)
Balance at Dec. 31, 2019		$ 2	449,428	(194,176)	255,254
Balance, Shares at Dec. 31, 2019		17,146,680
Balance at Sep. 30, 2019		$ 2	447,845	(185,365)	262,482
Balance, Shares at Sep. 30, 2019		17,125,938
Equity based compensation	[1]		1,404		1,404
Equity based compensation, Shares	[1]	13,259
Stock option exercises			200		200
Stock option exercises, Shares		8,000
Shares withheld for taxes			(21)		(21)
Shares withheld for taxes, Shares		(517)
Net loss				(8,811)	(8,811)
Balance at Dec. 31, 2019		$ 2	$ 449,428	$ (194,176)	$ 255,254
Balance, Shares at Dec. 31, 2019		17,146,680

[1] includes restricted shares