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Debt - Additional Information (Detail) - USD ($)				3 Months Ended		6 Months Ended
	Apr. 29, 2015	Dec. 19, 2014	Nov. 15, 2013	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Debt Instrument [Line Items]
Proceeds from additional equity offering (more than)	$ 22,300,000
Non-cash interest expense amortization of debt discount (less than $0.1 million each for Term Loan B and Term Loan C)				$ 100,000	$ 100,000	$ 100,000	$ 200,000
FIrst Warrants | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Number of shares received from warrants received to purchase common stock (in shares)		13,927
Fair value of warrants issued		$ 400,000
Second Warrants | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Number of shares received from warrants received to purchase common stock (in shares)		25,641
Fair value of warrants issued		$ 200,000
Hercules Warrants | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Number of shares received from warrants received to purchase common stock (in shares)		58,823
Warrant exercise price (in dollars per share)	$ 9.41	$ 11.00
Term Loan
Debt Instrument [Line Items]
Interest expense, debt				100,000	300,000	300,000	600,000
Term Loan | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Covenant, unrestricted cash balance requirement				2,000,000		2,000,000
Term Loan B | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Debt, face amount			$ 10,000,000.0
Net proceeds from debt			$ 9,800,000
Interest rate, stated percentage			11.00%
Outstanding principal balance				700,000		700,000
End of term fee						500,000
Minimum amount of proceeds from specified asset dispositions for mandatory prepayment feature				1,000,000.0		1,000,000.0
Debt discount			$ 200,000
Term Loan B | Hercules Warrants | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Unamortized discount (premium) and debt issuance costs		$ 1,000,000
Non-cash interest expense amortization of debt discount (less than $0.1 million each for Term Loan B and Term Loan C)				100,000	100,000	100,000
Term Loan C | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Debt, face amount		1,500,000.0
Net proceeds from debt		$ 1,400,000
Interest rate, stated percentage		11.00%
End of term fee						$ 100,000
Debt discount			$ 100,000
Debt instrument, maturity date						Jun. 01, 2017
Proceeds from additional equity offering (more than)				10,000,000
Term Loan C | Hercules Warrants | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Unamortized discount (premium) and debt issuance costs		$ 300,000
Non-cash interest expense amortization of debt discount (less than $0.1 million each for Term Loan B and Term Loan C)				$ 100,000	$ 100,000	$ 100,000	$ 100,000
Prime Rate | Term Loan B | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Debt instrument, basis spread on prime rate			3.75%
Prime Rate | Term Loan C | Senior Secured Loan | Hercules Technology Growth Capital
Debt Instrument [Line Items]
Debt instrument, basis spread on prime rate		3.75%

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Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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