Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Class A Common Stock	Series A-1 Preferred Stock	Series B Preferred Stock	Additional Paid-in Capital	Retained Earnings	Accumulated other comprehensive loss
Beginning balance at Dec. 31, 2015	$ 180,497	$ 142,638			$ 10,270	$ 28,349	$ (760)
Beginning balance (in shares) at Dec. 31, 2015		7,521,788
Sale of common stock, net of offering costs	71,817	$ 14			71,803
Sale of common stock, net of offering costs (in shares)		13,800,000
Shares issued for asset acquisition	5,499				5,499
Shares issued for asset acquisition (in shares)		500,227
Stock-based compensation	448				448
Foreign currency translation					(760)		$ 760
Net loss	(98,700)					(98,700)
Ending balance at Dec. 31, 2016	159,561	$ 142,652			87,260	(70,351)
Ending balance (in shares) at Dec. 31, 2016		21,822,015
Shares issued for asset acquisition	10,795			$ 3	10,792
Shares issued for asset acquisition (in shares)			5,400	2,684,632
Conversion of Series A-2 Preferred	75,504				75,504
Conversion of Series A-2 Preferred (in shares)			76,577
Conversion of Series B Preferred		$ 3		$ (3)
Conversion of Series B Preferred (in shares)		2,684,632		(2,684,632)
Payment-in-kind dividends (in shares)			1,991
Stock-based compensation	1,315				1,315
Net loss	(43,485)					(43,485)
Ending balance at Dec. 31, 2017	$ 203,690	$ 142,655			$ 174,871	$ (113,836)
Ending balance (in shares) at Dec. 31, 2017		24,506,647	83,968