Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Accrued Liabilities
Accrued offering costs	$ 60
Legal costs	166	$ 54
Accrued compensation costs	303	706
Other research and development expenses	339	1,259
Other general and administrative expenses	134	94
Total	$ 1,002	$ 2,113