Summary of Common Stock Reserved for Future Issuance (Detail)	Sep. 30, 2016 shares
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Common stock reserved for future issuance	4,131,706
Warrant
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Common stock reserved for future issuance	571,878
Stock Options And Restricted Stock Units
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Common stock reserved for future issuance	2,557,601
Bluehill AG
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Common stock reserved for future issuance	10,355
Stock Incentive Plan Twenty Eleven
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Common stock reserved for future issuance	697,984
ESPP
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Common stock reserved for future issuance	293,888