Shares of Common Stock Authorized and Reserved for Future Issuance (Detail)	Sep. 30, 2013
Class of Stock [Line Items]
Total common stock authorized and reserved for future issuance	11,449,958
Option To purchase common stock
Class of Stock [Line Items]
Total common stock authorized and reserved for future issuance	9,488,881
Option available for future issuance
Class of Stock [Line Items]
Total common stock authorized and reserved for future issuance	1,411,490
Series A convertible preferred stock warrant
Class of Stock [Line Items]
Total common stock authorized and reserved for future issuance	411,288
Common stock warrants
Class of Stock [Line Items]
Total common stock authorized and reserved for future issuance	138,299