CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net Loss	$ (18,753)	$ (2,986)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	1,886	687
Depreciation expense	4	1
Non-cash interest expense	280
Change in fair value of warrant liability	454
Change in fair value of derivative liability	(289)	3
Change in fair value of contingent equity liability	3,375
Loss from equity method investment	218
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(480)	125
Accounts payable	2,656	63
Accrued expenses	2,991	562
Other long-term liabilities	6
Net cash used in operating activities	(7,652)	(1,545)
Cash flows from investing activities:
Purchases of property and equipment	(21)
Purchase of equity method investment	(1,624)
Decrease in restricted cash	67
Net cash used in investing activities	(1,578)
Cash flows from financing activities:
Proceeds from issuance of common shares		3,003
Proceeds from issuance of Series A preferred shares	40,000
Payments of offering costs	(2,049)	(23)
Net cash provided by financing activities	37,951	2,980
Net increase in cash	28,721	1,435
Cash at beginning of period	23,565	1,460
Cash at end of period	52,286	$ 2,895
Supplemental disclosure of cash flow information:
Cash paid for interest	25
Supplemental disclosure of non-cash investing and financing activities:
Deferred offering costs included in accounts payable and accrued expenses	1,515
Deferred Series A offering costs included in accrued expenses	65
Beneficial conversion feature on Series A preferred shares	12,006
Accretion of beneficial conversion feature on series A preferred shares	(4,000)
Issuance of Series A preferred shares as payment of offering costs	1,242
Issuance of common shares as payment for equity investment (Note 5)	$ 352