Summary of Common Stock Reserved for Future Issuance (Detail)	Sep. 30, 2017 shares
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Common stock reserved for future issuance	3,892,838
Exercise of Outstanding Stock Options and Vesting of RSUs
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Common stock reserved for future issuance	2,374,385
ESPP
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Common stock reserved for future issuance	293,888
Shares Issuable to Settle Liability
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Common stock reserved for future issuance	53,880
Shares of Common Stock Available for Grant Under the 2011 Plan
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Common stock reserved for future issuance	395,330
Noncontrolling Interest in Bluehill AG
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Common stock reserved for future issuance	10,355
Warrants to Purchase Common Stock
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range [Line Items]
Common stock reserved for future issuance	765,000