Warrants and Derivative Liabilities - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2013	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015	Dec. 19, 2014	Nov. 13, 2014	Apr. 04, 2012
Derivative [Line Items]
Change in fair value of derivatives and warrants		$ 1,304	$ (228)	$ 3,963
Hercules warrants
Derivative [Line Items]
Change in fair value of derivatives and warrants		0	0	0
November 2014 warrant
Derivative [Line Items]
Change in fair value of derivatives and warrants		800	100	(1,800)
Common stock units offered (in shares)						909,090
Warrant to purchase one share of common stock (in shares)						0.9
Number of warrants issued to purchase common stock (in shares)						818,181
Sale of stock, price per share (in dollars per share)						$ 9.33
Capital Ventures International | Exchanged warrants
Derivative [Line Items]
Change in fair value of derivatives and warrants		$ 400	$ 100	$ 1,900
Senior convertible debt | Capital Ventures International | Original warrants
Derivative [Line Items]
Number of shares received from warrants received to purchase common stock (in shares)							309,406
Senior convertible debt | Capital Ventures International | Exchanged warrants
Derivative [Line Items]
Warrant exercise, waiting period	6 months
Warrant exercise period	5 years
Exercise price (in dollars per share)	$ 15.70
Senior convertible debt | Capital Ventures International | Maximum | Exchanged warrants
Derivative [Line Items]
Beneficial ownership limitation percentage	4.99%
Beneficial ownership, limitation option, percentage	9.99%
Required notification period	61 days
Term debt | Hercules warrants | Hercules Technology Growth Capital
Derivative [Line Items]
Number of shares received from warrants received to purchase common stock (in shares)					58,823
Exercise price (in dollars per share)		$ 9.38			$ 11.00