Nature of Operations (Details) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended		12 Months Ended
	Jul. 31, 2017	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Liquidity
Net loss attributable to common shareholders				$ (57,600)	$ (55,800)	$ (88,600)
Accumulated deficit		$ 1,118,177		1,051,467
Net cash used in operating activities		58,335	$ 15,761
Net outflows from fluctuations in working capital and other assets and liabilitie		24,300
Noncash gains		32,700
Cash and cash equivalents		2,090	66,040	46,014	$ 63,961
Net working capital		20,000		$ 44,400
Net cash used in investing activities		(20,545)	(28,842)
Net cash provided by financing activities		34,798	46,614
Proceeds from exercise of warrants		17,702	$ 111
Remaining lease payment		$ 45,321
Subsequent event
Liquidity
Proceeds from sale/leaseback	$ 13,600
Increase in term loan facility	20,000
Additional amount borrowed under term loan	$ 20,000