Consolidated Statements of Convertible Preferred Stock and Stockholders' Equity (Deficit) (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Deficit [Member]	Convertible Preferred Stock [Member]	Convertible Preferred Stock [Member] Series E Preferred Stock [Member]	Convertible Preferred Stock [Member] Series F Convertible Preferred Stock [Member]
Stockholders Equity, Beginning Balance at Mar. 31, 2012	$ (17,731)	$ 15	$ 1,202	$ (263)		$ (18,685)
Temporary Equity, Beginning Balance at Mar. 31, 2012							36,150
Stockholders Equity, Beginning Balance, Shares at Mar. 31, 2012		15,252,000		260,000
Temporary Equity, Beginning Balance, Shares at Mar. 31, 2012							17,910,000
Issuance of convertible preferred stock - net of issuance cost								59,767
Issuance of convertible preferred stock - net of issuance cost, Shares								3,447,000
Issuance of common stock upon exercise of stock options	255	1	254
Issuance of common stock upon exercise of stock options, Share		504,000
Vesting of early exercised options	12		12
Stock-based compensation expense	8,766		8,766
Net loss	(22,541)					(22,541)
Stockholders Equity, Ending Balance at Mar. 31, 2013	(31,239)	16	10,234	(263)		(41,226)
Temporary Equity, Ending Balance at Mar. 31, 2013							95,917
Stockholders Equity, Ending Balance, Shares at Mar. 31, 2013		15,756,000		260,000
Temporary Equity, Ending Balance, Shares at Mar. 31, 2013							21,357,000
Issuance of common stock upon exercise of stock options	294		294
Issuance of common stock upon exercise of stock options, Share		207,000
Issuance of restricted stock awards subject to vesting	0	0	0	0	0	0
Issuance of restricted stock awards subject to vesting, Shares		100,000
Stock-based compensation expense	6,505		6,505
Net loss	(40,225)					(40,225)
Stockholders Equity, Ending Balance at Mar. 31, 2014	(64,665)	16	17,033	(263)		(81,451)
Temporary Equity, Ending Balance at Mar. 31, 2014	95,917						95,917
Stockholders Equity, Ending Balance, Shares at Mar. 31, 2014		16,063,000		260,000
Temporary Equity, Ending Balance, Shares at Mar. 31, 2014	21,357,000						21,357,000
Issuance of convertible preferred stock - net of issuance cost									97,243
Issuance of convertible preferred stock - net of issuance cost, Shares									3,456,000
Conversion of convertible preferred stock to common stock upon initial public offering	193,160	25	193,135				(193,160)
Conversion of convertible preferred stock to common stock upon initial public offering, Shares		24,886,000					(24,813,000)
Reclassification of preferred stock warrant liabilities into additional paid-in capital	912		912
Reclassification of preferred stock warrant liabilities into additional paid-in capital, Shares	0	0	0	0	0	0
Issuance of common stock upon exercise of warrants	0	0	0	0	0	0
Issuance of common stock upon exercise of warrants, Shares		40,000
Issuance of common stock upon initial public offering-net of offering costs	119,924	6	119,918
Issuance of common stock upon initial public offering - net of offering costs, Shares		5,750,000
Issuance of common stock for acquisition of Few Ducks, S.L.	1,627		1,627
Issuance of common stock for acquisition of Few Ducks, S.L., Shares		108,000
Issuance of common stock for acquisition of Few Ducks, S.L.-Escrow Shares	188		188
Issuance of common stock upon exercise of stock options	1,209		1,209
Issuance of common stock upon exercise of stock options, Share	490,000	490,000
Issuance of restricted stock awards subject to vesting	0	0	0	0	0	0
Issuance of restricted stock awards subject to vesting, Shares		40,000
Stock-based compensation expense	12,649		12,649
Other comprehensive income, net	15				15
Net loss	(50,149)					(50,149)
Stockholders Equity, Ending Balance at Mar. 31, 2015	$ 214,870	$ 47	$ 346,671	$ (263)	$ 15	$ (131,600)
Stockholders Equity, Ending Balance, Shares at Mar. 31, 2015		47,377,000		260,000
Temporary Equity, Ending Balance, Shares at Mar. 31, 2015	0