Consolidated Statements of Changes in Stockholder's Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated other comprehensive income (loss)	LPC Offering	LPC Offering Common Stock	LPC Offering Additional Paid-In Capital	At The Market Offering	At The Market Offering Common Stock	At The Market Offering Additional Paid-In Capital
Beginning balance (in shares) at Dec. 31, 2018		65,290,879
Beginning balance at Dec. 31, 2018	$ 36,200	$ 1	$ 513,336	$ (475,667)	$ (1,470)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock—restricted stock (in shares)		2,588,450
Issuance of common stock--option exercise (in shares)		34,669
Issuance of common stock—option exercise	121		121
Issuance of common stock (in shares)		775,194
Issuance of common stock	3,000		3,000
Compensation expense related to issued stock options and restricted stock awards	2,106		2,106
Net loss	(14,344)			(14,344)
Other comprehensive income (loss)	218				218
Ending balance (in shares) at Jun. 30, 2019		68,689,192
Ending balance at Jun. 30, 2019	27,301	$ 1	518,563	(490,011)	(1,252)
Beginning balance (in shares) at Mar. 31, 2019		67,880,664
Beginning balance at Mar. 31, 2019	30,387	$ 1	514,484	(483,248)	(850)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock—restricted stock (in shares)		(1,335)
Issuance of common stock--option exercise (in shares)		34,669
Issuance of common stock—option exercise	121		121
Issuance of common stock (in shares)		775,194
Issuance of common stock	3,000		3,000
Compensation expense related to issued stock options and restricted stock awards	958		958
Net loss	(6,763)			(6,763)
Other comprehensive income (loss)	(402)				(402)
Ending balance (in shares) at Jun. 30, 2019		68,689,192
Ending balance at Jun. 30, 2019	$ 27,301	$ 1	518,563	(490,011)	(1,252)
Beginning balance (in shares) at Dec. 31, 2019	70,427,400	70,427,400
Beginning balance at Dec. 31, 2019	$ 16,347	$ 1	521,356	(504,145)	(865)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock—restricted stock (in shares)		3,657,838
Issuance of common stock—restricted stock	0
Ending balance (in shares) at Mar. 31, 2020		71,505,724
Ending balance at Mar. 31, 2020	$ 9,515	$ 1	523,265	(513,498)	(253)
Beginning balance (in shares) at Dec. 31, 2019	70,427,400	70,427,400
Beginning balance at Dec. 31, 2019	$ 16,347	$ 1	521,356	(504,145)	(865)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock—restricted stock (in shares)		3,736,162
Issuance of common stock—restricted stock	2
Issuance of common stock (in shares)							1,200,000			740,043
Issuance of common stock						$ 1,317		$ 1,317	$ 705		$ 705
Compensation expense related to issued stock options and restricted stock awards	1,611		1,611
Net loss	(11,488)
Other comprehensive income (loss)	$ (51)				(51)
Ending balance (in shares) at Jun. 30, 2020	76,103,605	76,103,605
Ending balance at Jun. 30, 2020	$ 8,443	$ 1	524,991	(515,633)	(916)
Beginning balance (in shares) at Mar. 31, 2020		71,505,724
Beginning balance at Mar. 31, 2020	9,515	$ 1	523,265	(513,498)	(253)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock (in shares)							200,000			740,043
Issuance of common stock						$ 174		$ 174	$ 707		$ 707
Compensation expense related to issued stock options and restricted stock awards	845		845
Net loss	(2,135)
Other comprehensive income (loss)	$ (663)				(663)
Ending balance (in shares) at Jun. 30, 2020	76,103,605	76,103,605
Ending balance at Jun. 30, 2020	$ 8,443	$ 1	$ 524,991	$ (515,633)	$ (916)