Description of the Business and Liquidity (Details) $ in Thousands	3 Months Ended
	Sep. 30, 2017 USD ($) item shares	Dec. 31, 2016 USD ($)
Number of dose forms for modulator | item	3
Liquidity
Accumulated deficit	$ (139,989)	$ (125,829)
Secondary public offering
Liquidity
Common stock issued (in shares) | shares	10,733,334
Proceeds from issuance of common stock, net of issuance costs	$ 37,700