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Term loan facility additional interest rate during event of default.

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Exercise price per share or per unit of warrants or rights outstanding.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Including the current and noncurrent portions, aggregate carrying value as of the balance sheet date of loans payable (with maturities initially due after one year or beyond the operating cycle if longer).

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Loan Agreements - Additional Information (Detail)		1 Months Ended				3 Months Ended		6 Months Ended
Loan Agreements - Additional Information (Detail)	Jan. 08, 2015 USD ($) Tranches $ / shares shares	Jan. 31, 2015 USD ($)	Aug. 31, 2012 USD ($)	Mar. 31, 2012 USD ($)	Dec. 31, 2011 USD ($) $ / shares shares	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Aug. 31, 2012 USD ($)	Dec. 31, 2015 USD ($)	Dec. 15, 2015 USD ($)	Nov. 24, 2015 USD ($)	Apr. 30, 2014 shares
Debt Instrument [Line Items]
Proceeds from sale of common stock						$ 41,000	$ 2,411,000
Proceeds from loan payable							$ 15,000,000
Hercules Loan Agreement [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Prior written notice period to prepay term loan						7 days
Loan and Security Agreement with Lighthouse Capital [Member] \| Loans payable [Member]
Debt Instrument [Line Items]
Loan and security agreement, maximum borrowing capacity					$ 10,000,000
Proceeds from loan payable			$ 5,000,000	$ 5,000,000				$ 10,000,000
Loan and security agreement, borrowings repayment period					36 months
Debt instrument stated interest rate					8.25%
Loan and security agreement, borrowings repayment start date					Dec. 01, 2012
Line of credit facility, additional interest payment						$ 600,000
Repayments of notes payable		$ 3,600,000
Unamortized discount on debt, relating to warrants		200,000
Loan and Security Agreement with Lighthouse Capital [Member] \| Loans payable [Member] \| Series D Convertible Preferred Stock [Member]
Debt Instrument [Line Items]
Exercise price of warrant \| $ / shares					$ 12.04
Warrant expiration date					2021-12
Warrant expiration period					10 years
Loan and Security Agreement with Lighthouse Capital [Member] \| Loans payable [Member] \| Common Stock [Member]
Debt Instrument [Line Items]
Warrant to purchase stock, number of securities called by warrants or rights \| shares												66,436
Loan and Security Agreement with Lighthouse Capital [Member] \| Maximum [Member] \| Loans payable [Member] \| Series D Convertible Preferred Stock [Member]
Debt Instrument [Line Items]
Warrant to purchase stock, number of securities called by warrants or rights \| shares					66,436
Hercules Technology Growth Capital, Inc. [Member] \| Hercules Loan Agreement [Member] \| Stock Purchase Agreement [Member]
Debt Instrument [Line Items]
Issuance of common stock, shares \| shares	135,501
Issuance/sale of stock, price per share \| $ / shares	$ 7.38
Proceeds from sale of common stock	$ 1,000,000
Hercules Technology Growth Capital, Inc. [Member] \| Hercules Loan Agreement [Member] \| Term Loan [Member]
Debt Instrument [Line Items]
Loan and security agreement, maximum borrowing capacity	$ 26,000,000
Amount outstanding under the Term Loan						$ 19,100,000			$ 21,000,000
Term loan facility, maturity date	Jul. 01, 2018
Term loan facility, interest rate terms						The Term Loan will mature on July 1, 2018. Each advance under the Term Loan accrues interest at a floating per annum rate equal to the greater of (i) 7.30% or (ii) the sum of 7.30% plus the prime rate minus 5.75%. The Term Loan provided for interest-only payments on a monthly basis until December 31, 2015.
Additional interest rate during an event of default	5.00%
Final payment as percentage of aggregate original principal amount	6.70%
Term loan facility, interest rate	7.30%
Debt prepayment charge, after twelve months	2.00%
Debt prepayment charge, after twenty-four months	1.00%
Class of warrant or right, date until which warrants exercisable	Jan. 08, 2020
Estimated fair value of warrant		$ 824,000
Hercules Technology Growth Capital, Inc. [Member] \| Hercules Loan Agreement [Member] \| Term Loan [Member] \| Common Stock [Member]
Debt Instrument [Line Items]
Exercise price of warrant \| $ / shares	$ 6.05
Warrant to purchase stock, number of securities called by warrants or rights \| shares	171,901
Hercules Technology Growth Capital, Inc. [Member] \| Hercules Loan Agreement [Member] \| Term Loan [Member] \| Prime Rate [Member]
Debt Instrument [Line Items]
Term loan facility, interest rate spread	5.75%
Hercules Technology Growth Capital, Inc. [Member] \| Hercules Loan Agreement [Member] \| Term Loan [Member] \| Borrowing One [Member]
Debt Instrument [Line Items]
Loan and security agreement, maximum borrowing capacity	$ 15,000,000
Hercules Technology Growth Capital, Inc. [Member] \| Hercules Loan Agreement [Member] \| Term Loan [Member] \| Second Tranche [Member]
Debt Instrument [Line Items]
Loan and security agreement, maximum borrowing capacity											$ 6,000,000
Hercules Technology Growth Capital, Inc. [Member] \| Hercules Loan Agreement [Member] \| Term Loan [Member] \| Up on Meeting Certain Clinical Milestone on or Prior to Dec. 15, 2015 [Member]
Debt Instrument [Line Items]
Loan and security agreement, maximum borrowing capacity										$ 5,000,000
Hercules Technology Growth Capital, Inc. [Member] \| Hercules Loan Agreement [Member] \| Term Loan [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Number of tranches \| Tranches	3