Condensed Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Condensed Statements of Cash Flows
Net loss	$ (7,496)	$ (2,103)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation	836	123
Non-cash interest on convertible notes to related parties		31
Non-cash interest on convertible notes		78
Non-cash discount amortization on convertible notes to related parties		(55)
Non-cash discount amortization on convertible notes		(159)
Revaluation of premium conversion derivative		22
Change in assets and liabilities:
Prepaid expenses and other assets	161	(1)
Accounts payable	1,473	(242)
Accrued and other liabilities	(1,197)	294
Net cash used in operating activities	(6,223)	(2,056)
Financing activities
Proceeds from issuance of convertible notes		50
Proceeds from issuance of convertible notes to related parties		101
Exercise of stock options	3
Proceeds from offering	12,541
Offering costs	(1,072)	(86)
Net cash provided by financing activities	11,472	65
Net increase in cash and cash equivalents	5,249	(1,991)
Cash and cash equivalents at beginning of period	24,033	3,620
Cash and cash equivalents at end of period	29,282	1,629
Supplemental non-cash financing transactions:
Redemption value change of Series A preferred stock		149
Bifurcation of premium conversion derivative related to convertible notes		9
Offering costs	$ 147	$ 46