Fair Value of Financial Assets and Liabilities - Rollforward of Liabilities Measured by Level 3 Inputs (Details) - USD ($) $ in Thousands		6 Months Ended
	Jan. 26, 2018	Jun. 30, 2018	Jun. 30, 2017
Rollforward of Liabilities Measured by Level 3 Inputs:
Reclassification to equity	$ (5,203)	$ (5,203)	$ 0
Issuance of common shares in settlement of contingent equity liability		0	(32,020)
Warrant Liability
Rollforward of Liabilities Measured by Level 3 Inputs:
Beginning balance		4,021	780
Change in fair value		1,182	3,083
Reclassification to equity		(5,203)
Issuance of common shares in settlement of contingent equity liability			0
Ending balance		0	3,863
Derivative Liability
Rollforward of Liabilities Measured by Level 3 Inputs:
Beginning balance		0	512
Change in fair value		0	(512)
Reclassification to equity		0
Issuance of common shares in settlement of contingent equity liability			0
Ending balance		0	0
Contingent Equity Liability
Rollforward of Liabilities Measured by Level 3 Inputs:
Beginning balance		0	18,938
Change in fair value		0	13,082
Reclassification to equity		0
Issuance of common shares in settlement of contingent equity liability			(32,020)
Ending balance		$ 0	$ 0