Common Stock and Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Mar. 31, 2016
Class of Stock [Line Items]
Common stock, shares authorized (in shares)		100,000,000		100,000,000		100,000,000
Common stock, par value (in usd per share)		$ 0.001		$ 0.001		$ 0.001
Stock-based compensation expense		$ 8,118	$ 6,356	$ 23,719	$ 16,603
Fair value granted restricted stock awards shares of common stock (in shares)				1,252,000
Grant date fair value of restricted stock awards (in usd per share)				$ 28.13
Stock options granted (in shares)				327,000
Unrecognized stock-based compensation cost related to outstanding unvested stock awards		$ 21,600		$ 21,600
Stock-based compensation cost expected to be recognized over weighted-average period		1 year 11 months 17 days
Expected to vest unrecognized stock-based compensation cost related to outstanding unvested stock options		$ 56,100		$ 56,100
Unvested Stock Options
Class of Stock [Line Items]
Stock based compensation cost is expected to be recognized over a weighted-average period		2 years 10 months 20 days
ESPP shares
Class of Stock [Line Items]
Shares reserved for issuance under plan (in shares)		1,000,000		1,000,000
Additional shares available for issuance under the plan (in shares)	500,000
Percentage of common stock shares increased under the plan	1.00%
Common stock purchased under Employee Stock Purchase Plan (in shares)		0	0	118,658	0
Stock-based compensation expense		$ 500	$ 300	$ 1,400	$ 500
Shares available for issuance (in shares)		1,741,172		1,741,172
2008 Equity Incentive Plan
Class of Stock [Line Items]
Shares available for issuance (in shares)		0		0
2014 Equity Incentive Plan
Class of Stock [Line Items]
Shares reserved for issuance under plan (in shares)	5,000,000
Shares available for issuance (in shares)		8,084,490		8,084,490
Shares available for grant under plan (in shares)	5,184,878
Increase in shares available under plan, percentage of outstanding common stock shares	5.00%