Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Total
Balance at Dec. 31, 2017	$ 424	$ 114,302	$ 8,727	$ 123,453
Balance (in shares) at Dec. 31, 2017	42,398,140
Issuance of common stock upon exercise of stock options and warrants	$ 0	17	0	17
Issuance of common stock upon exercise of stock options and warrants (in shares)	5,000
Value of share-based arrangements	$ 0	212	0	212
Value of share-based arrangements (in shares)	0
Net loss	$ 0	0	(33,672)	(33,672)
Balance at Jun. 30, 2018	$ 424	114,531	(24,945)	90,010
Balance (in shares) at Jun. 30, 2018	42,403,140
Balance at Mar. 31, 2018	$ 424	114,345	5,671	120,440
Balance (in shares) at Mar. 31, 2018	42,403,140
Value of share-based arrangements	$ 0	186	0	186
Value of share-based arrangements (in shares)	0
Net loss	$ 0	0	(30,616)	(30,616)
Balance at Jun. 30, 2018	$ 424	114,531	(24,945)	90,010
Balance (in shares) at Jun. 30, 2018	42,403,140
Balance at Dec. 31, 2018	$ 426	115,719	(46,932)	69,213
Balance (in shares) at Dec. 31, 2018	42,602,431
Issuance of common stock upon exercise of stock options and warrants	$ 0	9	0	9
Issuance of common stock upon exercise of stock options and warrants (in shares)	10,000
Value of share-based arrangements	$ 0	628	0	628
Value of share-based arrangements (in shares)	0
Net loss	$ 0	0	(17,836)	(17,836)
Balance at Jun. 30, 2019	$ 426	116,356	(64,768)	52,014
Balance (in shares) at Jun. 30, 2019	42,612,431
Balance at Mar. 31, 2019	$ 426	116,096	(50,971)	65,551
Balance (in shares) at Mar. 31, 2019	42,602,431
Issuance of common stock upon exercise of stock options and warrants	$ 0	9	0	9
Issuance of common stock upon exercise of stock options and warrants (in shares)	10,000
Value of share-based arrangements	$ 0	251	0	251
Net loss	0	0	(13,797)	(13,797)
Balance at Jun. 30, 2019	$ 426	$ 116,356	$ (64,768)	$ 52,014
Balance (in shares) at Jun. 30, 2019	42,612,431