Common Stock and Stockholders' Equity (Deficit) - Schedule of Shares of Common Stock Reserved for Future Issuance (Detail)	Mar. 31, 2015	Mar. 31, 2014
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	16,423,000	28,627,000
Restricted Stock Units [Member]
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	723,000
Available for Future Stock Option and RSU Grants [Member]
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	5,149,000	298,000
Available for Future Employee Stock Purchase Plan Awards [Member]
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	1,000,000
Convertible Preferred Stock [Member]
Class of Stock [Line Items]
Shares of common stock reserved for future issuance		21,357,000
Warrants [Member]
Class of Stock [Line Items]
Shares of common stock reserved for future issuance		49,000
Common Stock Options Outstanding [Member]
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	9,422,000	6,923,000
Common Stock [Member]
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	129,000