Fair Value of Financial Assets and Liabilities - Fair values of the company's liabilities (Details) - USD ($)	1 Months Ended	3 Months Ended
	May 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Fair values of the company's liabilities
Reclassification to equity		$ (5,203,000)
Transfer between levels 1 to level 2		0	$ 0
Transfer between levels 2 to level 1		0	0
Transfer in and out of level 3		0	0
Recognized fair value of BCF as a reduction to series A preferred shares and corresponding adjustment to additional paid in capital			(12,006,000)
Series A Convertible Preferred Shares
Fair values of the company's liabilities
Recognized fair value of BCF as a reduction to series A preferred shares and corresponding adjustment to additional paid in capital		12,006,000
Shares issued on conversion of preferred stock	9,358,560
Warrants to purchase common shares
Fair values of the company's liabilities
Balance at the beginning		4,021,000	780,000
Change in fair value		1,182,000	454,000
Reclassification to equity		$ (5,203,000)
Balance at the end			1,234,000
Derivative Liability
Fair values of the company's liabilities
Balance at the beginning			512,000
Change in fair value			(289,000)
Balance at the end			223,000
Contingent Equity Liability
Fair values of the company's liabilities
Balance at the beginning			18,938,000
Change in fair value			3,375,000
Balance at the end			$ 22,313,000