Debt	6 Months Ended
Sep. 30, 2015
Debt Disclosure [Abstract]
Debt	10. Debt On June 5, 2012, the Company entered into The Loan and Security Agreement with Hercules (the “Term Loan”), under which the Company borrowed $10.0 million. After closing fees and expenses, the net proceeds to the Company were $9.7 million. The Term Loan bears an interest rate equal to 11% plus the percentage, if any, by which the prime rate as reported by The Wall Street Journal exceeds 3.75%. The Company made interest-only payments from July 1, 2012 through October 31, 2012, after which the Company began repaying the Term Loan in equal monthly installments ending on December 1, 2014, when the loan was repaid in full. In addition, Hercules received a warrant (the “First Warrant”) to purchase 13,927 shares of common stock, exercisable at an initial strike price of $35.90 per share, subject to adjustment, until December 5, 2017. Due to certain adjustment provisions within the warrant, it qualified for liability accounting and the fair value of $0.4 million was recorded upon issuance, which the Company recorded as a debt discount and a warrant liability. The total debt discount including the First Warrant, end of term fee and legal and origination costs of $1.2 million was amortized into interest expense over the term of the Term Loan using the effective interest method. Under this method, interest expense was recognized each period until the debt instrument reached maturity. During the three and six months ended September 30, 2014, the Company recorded non-cash interest expense for amortization of the debt discount related to the Term Loan of less than $0.1 million and $0.1 million, respectively. On November 15, 2013, the Company amended the Term Loan with Hercules and entered into a new term loan (the “New Term Loan B”), borrowing an additional $10.0 million. After closing fees and expenses, the net proceeds to the Company for the New Term Loan B were $9.8 million. The New Term Loan B bears the same interest rate as the Term Loan. The Company is repaying the New Term Loan B in equal monthly installments ending on November 1, 2016. The principal balance of the New Term Loan B is approximately $5.7 million as of September 30, 2015. Hercules received a warrant (the “Second Warrant”) to purchase 25,641 shares of common stock, exercisable at an initial strike price of $19.50 per share, subject to adjustment, until May 15, 2019. In addition, the exercise price of the First Warrant was reduced to $19.50 per share. (See Note 11, “Warrants and Derivative Liabilities,” for a discussion on both warrants and the valuation assumptions used.) The Company will pay an end of term fee of $0.5 million upon the earlier of maturity or prepayment of the New Term Loan B. The Company has accrued the end of term fee and recorded a corresponding amount into the debt discount. The New Term Loan B includes a mandatory prepayment feature which allows Hercules the right to use any of the Company’s net proceeds from specified asset dispositions greater than $1.0 million in a calendar year to pay off any outstanding accrued interest and principal balance on the New Term Loan B. The Company determined the fair value to be de-minimis for this feature. In addition, the Company incurred $0.2 million of legal and origination costs in the three months ended December 31, 2013, which have been recorded as a debt discount. The total debt discount including the Second Warrant, end of term fee and legal and origination costs of $1.0 million is being amortized into interest expense over the term of the New Term Loan B using the effective interest method. During the three and six months ended September 30, 2015, the Company recorded non-cash interest expense for amortization of the debt discount related to the New Term Loan B of $0.1 million and $0.2 million, respectively. During the three and six months ended September 30, 2014, the Company recorded non-cash interest expense for amortization of the debt discount related to the New Term Loan B of $0.1 million and $0.2 million, respectively. On December 19, 2014, the Company entered into an amendment with Hercules (the “Hercules Second Amendment”) and entered into a new term loan (the “New Term Loan C”), borrowing an additional $1.5 million. After closing fees and expenses, the net proceeds to the Company for the New Term Loan C were $1.4 million. The Term Loan, New Term Loan B and New Term Loan C are collectively referred to as the “Term Loans”. The New Term Loan C also bears the same interest rate as the other Term Loans. The Company will make interest only payments until maturity on June 1, 2017, when the loan is scheduled to be repaid in its entirety. The maturity date of the New Term Loan C was extended from March 1, 2017 to June 1, 2017 due to the Company’s April 2015 equity offering which raised more than $10 million in new capital before December 31, 2015. In conjunction with the Hercules Second Amendment, the First Warrant and Second Warrant were cancelled and replaced with the issuance of a new warrant (the “Warrant”) to purchase 58,823 shares of common stock at an exercise price of $11.00 per share, subject to adjustment. The Warrant expires on June 30, 2020. (See Note 11, “Warrants and Derivative Liabilities”, for a discussion on the Warrant and the valuation assumptions used.) The Company will pay an end of term fee of approximately $0.1 million upon earlier of maturity or prepayment of the New Term Loan C. The Company has accrued the end of term fee and recorded a corresponding amount in the debt discount. The New Term Loan C includes the same mandatory prepayment feature as the New Term Loan B. The Company determined the fair value to be de-minimus for this feature. In addition, the Company incurred approximately $0.1 million of legal and origination costs in the three months ended December 31, 2014, which have been recorded as a debt discount. The total debt discount, including the Warrant, end of term fee and legal and origination costs of $0.3 million is being amortized into interest expense over the term of the New Term Loan C using the effective interest method. During each of the three and six months ended September 30, 2015, the Company recorded non-cash interest expense for amortization of the debt discount related to the New Term Loan C of less than $0.1 million. If the maturity of any of the Term Loans is accelerated because of prepayment, then the amortization will be accelerated. The Term Loans are secured by substantially all of the Company’s existing and future assets, including a mortgage on real property owned by the Company’s wholly-owned subsidiary, ASC Devens LLC, and located at 64 Jackson Road, Devens, Massachusetts. The Term Loans contain certain covenants that restrict the Company’s ability to, among other things, incur or assume certain debt, merge or consolidate, materially change the nature of the Company’s business, make certain investments, acquire or dispose of certain assets, make guarantees or grant liens on its assets, make certain loans, advances or investments, declare dividends or make distributions or enter into transactions with affiliates. In addition, there is a covenant that requires the Company to maintain a minimum unrestricted cash balance (the “Minimum Threshold”) in the United States. As part of the Hercules Second Amendment, this Minimum Threshold was amended to be the lower of $5.0 million or the aggregate outstanding principal balance of the Term Loans. As a result of the Company’s April 2015 equity offering, the Minimum Threshold was reduced to the lesser of $2.0 million or the aggregate outstanding principal balance of the Term Loans. As of September 30, 2015, the Minimum Threshold was $2.0 million. The events of default under the Term Loans include, but are not limited to, failure to pay amounts due, breaches of covenants, bankruptcy events, cross defaults under other material indebtedness and the occurrence of a material adverse effect and/or change in control. In the case of a continuing event of default, Hercules may, among other remedies, declare due all unpaid principal amounts outstanding and any accrued but unpaid interest and foreclose on all collateral granted to Hercules as security under the Term Loans. Although the Company believes that it is in compliance with the covenants and restrictions under the Term Loans as of September 30, 2015, there can be no assurance that the Company will continue to be in compliance. Interest expense on the Term Loans for the three and six months ended September 30, 2015 was $0.3 million, and $0.6 million, respectively, which included $0.1 million and $0.2 million, respectively, of non-cash interest expense related to the amortization of the debt discount on the Term Loans. Interest expense on the Term Loans for the three and six months ended September 30, 2014, was $0.5 million, and $1.0 million, respectively, which included $0.2 million and $0.3 million, respectively, of non-cash interest expense related to the amortization of the debt discount on the Term Loans.

10. Debt

On June 5, 2012, the Company entered into The Loan and Security Agreement with Hercules (the “Term Loan”), under which the Company borrowed $10.0 million. After closing fees and expenses, the net proceeds to the Company were $9.7 million. The Term Loan bears an interest rate equal to 11% plus the percentage, if any, by which the prime rate as reported by The Wall Street Journal exceeds 3.75%. The Company made interest-only payments from July 1, 2012 through October 31, 2012, after which the Company began repaying the Term Loan in equal monthly installments ending on December 1, 2014, when the loan was repaid in full. In addition, Hercules received a warrant (the “First Warrant”) to purchase 13,927 shares of common stock, exercisable at an initial strike price of $35.90 per share, subject to adjustment, until December 5, 2017. Due to certain adjustment provisions within the warrant, it qualified for liability accounting and the fair value of $0.4 million was recorded upon issuance, which the Company recorded as a debt discount and a warrant liability. The total debt discount including the First Warrant, end of term fee and legal and origination costs of $1.2 million was amortized into interest expense over the term of the Term Loan using the effective interest method. Under this method, interest expense was recognized each period until the debt instrument reached maturity. During the three and six months ended September 30, 2014, the Company recorded non-cash interest expense for amortization of the debt discount related to the Term Loan of less than $0.1 million and $0.1 million, respectively.

On November 15, 2013, the Company amended the Term Loan with Hercules and entered into a new term loan (the “New Term Loan B”), borrowing an additional $10.0 million. After closing fees and expenses, the net proceeds to the Company for the New Term Loan B were $9.8 million. The New Term Loan B bears the same interest rate as the Term Loan. The Company is repaying the New Term Loan B in equal monthly installments ending on November 1, 2016. The principal balance of the New Term Loan B is approximately $5.7 million as of September 30, 2015. Hercules received a warrant (the “Second Warrant”) to purchase 25,641 shares of common stock, exercisable at an initial strike price of $19.50 per share, subject to adjustment, until May 15, 2019. In addition, the exercise price of the First Warrant was reduced to $19.50 per share. (See Note 11, “Warrants and Derivative Liabilities,” for a discussion on both warrants and the valuation assumptions used.) The Company will pay an end of term fee of $0.5 million upon the earlier of maturity or prepayment of the New Term Loan B. The Company has accrued the end of term fee and recorded a corresponding amount into the debt discount. The New Term Loan B includes a mandatory prepayment feature which allows Hercules the right to use any of the Company’s net proceeds from specified asset dispositions greater than $1.0 million in a calendar year to pay off any outstanding accrued interest and principal balance on the New Term Loan B. The Company determined the fair value to be de-minimis for this feature. In addition, the Company incurred $0.2 million of legal and origination costs in the three months ended December 31, 2013, which have been recorded as a debt discount. The total debt discount including the Second Warrant, end of term fee and legal and origination costs of $1.0 million is being amortized into interest expense over the term of the New Term Loan B using the effective interest method. During the three and six months ended September 30, 2015, the Company recorded non-cash interest expense for amortization of the debt discount related to the New Term Loan B of $0.1 million and $0.2 million, respectively. During the three and six months ended September 30, 2014, the Company recorded non-cash interest expense for amortization of the debt discount related to the New Term Loan B of $0.1 million and $0.2 million, respectively.

On December 19, 2014, the Company entered into an amendment with Hercules (the “Hercules Second Amendment”) and entered into a new term loan (the “New Term Loan C”), borrowing an additional $1.5 million. After closing fees and expenses, the net proceeds to the Company for the New Term Loan C were $1.4 million. The Term Loan, New Term Loan B and New Term Loan C are collectively referred to as the “Term Loans”. The New Term Loan C also bears the same interest rate as the other Term Loans. The Company will make interest only payments until maturity on June 1, 2017, when the loan is scheduled to be repaid in its entirety. The maturity date of the New Term Loan C was extended from March 1, 2017 to June 1, 2017 due to the Company’s April 2015 equity offering which raised more than $10 million in new capital before December 31, 2015. In conjunction with the Hercules Second Amendment, the First Warrant and Second Warrant were cancelled and replaced with the issuance of a new warrant (the “Warrant”) to purchase 58,823 shares of common stock at an exercise price of $11.00 per share, subject to adjustment. The Warrant expires on June 30, 2020. (See Note 11, “Warrants and Derivative Liabilities”, for a discussion on the Warrant and the valuation assumptions used.) The Company will pay an end of term fee of approximately $0.1 million upon earlier of maturity or prepayment of the New Term Loan C. The Company has accrued the end of term fee and recorded a corresponding amount in the debt discount. The New Term Loan C includes the same mandatory prepayment feature as the New Term Loan B. The Company determined the fair value to be de-minimus for this feature. In addition, the Company incurred approximately $0.1 million of legal and origination costs in the three months ended December 31, 2014, which have been recorded as a debt discount. The total debt discount, including the Warrant, end of term fee and legal and origination costs of $0.3 million is being amortized into interest expense over the term of the New Term Loan C using the effective interest method. During each of the three and six months ended September 30, 2015, the Company recorded non-cash interest expense for amortization of the debt discount related to the New Term Loan C of less than $0.1 million. If the maturity of any of the Term Loans is accelerated because of prepayment, then the amortization will be accelerated.

The Term Loans are secured by substantially all of the Company’s existing and future assets, including a mortgage on real property owned by the Company’s wholly-owned subsidiary, ASC Devens LLC, and located at 64 Jackson Road, Devens, Massachusetts. The Term Loans contain certain covenants that restrict the Company’s ability to, among other things, incur or assume certain debt, merge or consolidate, materially change the nature of the Company’s business, make certain investments, acquire or dispose of certain assets, make guarantees or grant liens on its assets, make certain loans, advances or investments, declare dividends or make distributions or enter into transactions with affiliates. In addition, there is a covenant that requires the Company to maintain a minimum unrestricted cash balance (the “Minimum Threshold”) in the United States. As part of the Hercules Second Amendment, this Minimum Threshold was amended to be the lower of $5.0 million or the aggregate outstanding principal balance of the Term Loans. As a result of the Company’s April 2015 equity offering, the Minimum Threshold was reduced to the lesser of $2.0 million or the aggregate outstanding principal balance of the Term Loans. As of September 30, 2015, the Minimum Threshold was $2.0 million. The events of default under the Term Loans include, but are not limited to, failure to pay amounts due, breaches of covenants, bankruptcy events, cross defaults under other material indebtedness and the occurrence of a material adverse effect and/or change in control. In the case of a continuing event of default, Hercules may, among other remedies, declare due all unpaid principal amounts outstanding and any accrued but unpaid interest and foreclose on all collateral granted to Hercules as security under the Term Loans.

Although the Company believes that it is in compliance with the covenants and restrictions under the Term Loans as of September 30, 2015, there can be no assurance that the Company will continue to be in compliance.

Interest expense on the Term Loans for the three and six months ended September 30, 2015 was $0.3 million, and $0.6 million, respectively, which included $0.1 million and $0.2 million, respectively, of non-cash interest expense related to the amortization of the debt discount on the Term Loans. Interest expense on the Term Loans for the three and six months ended September 30, 2014, was $0.5 million, and $1.0 million, respectively, which included $0.2 million and $0.3 million, respectively, of non-cash interest expense related to the amortization of the debt discount on the Term Loans.