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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 |  |

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