Convertible Preferred Stock - Summary of Outstanding Convertible Preferred Stock (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 17, 2014	Mar. 31, 2014
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized	10,000,000	24,962,000	22,323,000
Convertible Preferred Stock, Shares Issued and Outstanding		24,813,000	21,357,000
Convertible Preferred Stock, Liquidation Preference		$ 196,383	$ 96,383
Series A Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized		7,028,000	7,028,000
Convertible Preferred Stock, Shares Issued and Outstanding		7,000,000	7,000,000
Convertible Preferred Stock, Liquidation Preference		$ 3,500	$ 3,500
Series B Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized		6,492,000	6,492,000
Convertible Preferred Stock, Shares Issued and Outstanding		6,492,000	6,492,000
Convertible Preferred Stock, Liquidation Preference		$ 7,940	$ 7,940
Series C Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized		2,852,000	2,852,000
Convertible Preferred Stock, Shares Issued and Outstanding		2,852,000	2,852,000
Convertible Preferred Stock, Liquidation Preference		$ 9,943	$ 9,943
Series D Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized		1,643,000	1,643,000
Convertible Preferred Stock, Shares Issued and Outstanding		1,566,000	1,566,000
Convertible Preferred Stock, Liquidation Preference		$ 15,000	$ 15,000
Series E Preferred Stock [Member]
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized		3,447,000	4,308,000
Convertible Preferred Stock, Shares Issued and Outstanding		3,447,000	3,447,000
Convertible Preferred Stock, Liquidation Preference		$ 60,000	$ 60,000
Series F Convertible Preferred Stock [Member]
Temporary Equity [Line Items]
Convertible preferred stock, shares authorized		3,500,000
Convertible Preferred Stock, Shares Issued and Outstanding		3,456,000
Convertible Preferred Stock, Liquidation Preference		$ 100,000