Debt	3 Months Ended
Jun. 30, 2016
Debt Disclosure [Abstract]
Debt	Debt Senior Secured Term Loans On November 15, 2013, the Company amended its existing Loan and Security Agreement with Hercules and entered into a new term loan (the “Term Loan B”), borrowing $10.0 million. After closing fees and expenses, the net proceeds to the Company for the Term Loan B were $9.8 million. The Term Loan B bears an interest rate of 11% plus the percentage, if any, by which the prime rate as reported by the Wall Street Journal exceeds 3.75%. The Company is repaying the Term Loan B in equal monthly installments ending on November 1, 2016. The principal balance of the Term Loan B is approximately $1.7 million as of June 30, 2016. The Company will pay an end of term fee of $0.5 million upon the earlier of maturity or prepayment of the Term Loan B. The Company has accrued the end of term fee and recorded a corresponding amount into the debt discount. The 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 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 at inception of the loan, which have been recorded as a debt discount. On December 19, 2014, the Company entered into a second amendment with Hercules (the “Hercules Second Amendment”) and entered into a new term loan, borrowing an additional $1.5 million (the “Term Loan C”). After closing fees and expenses, the net proceeds to the Company for the Term Loan C were $1.4 million. The Term Loan B and Term Loan C are collectively referred to as the “Term Loans”. The Term Loan C also bears the same interest rate as the Term Loan B. 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 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. The Company will pay an end of term fee of approximately $0.1 million upon earlier of maturity or prepayment of the Term Loan C. The Company has accrued the end of term fee and recorded a corresponding amount in the debt discount. The Term Loan C includes the same mandatory prepayment feature as the 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 at inception of the loan, which have been recorded as a debt discount. Hercules received warrants to purchase 13,927 shares of common stock (the “First Warrant”) and 25,641 shares of common stock (the “Second Warrant”) in conjunction with a prior term loan which has been repaid in full and the Term Loan B. Due to certain adjustment provisions within the warrants, they qualified for liability accounting. The fair value of the warrants, $0.4 million and $0.2 million, respectively, was recorded upon issuance to debt discount and a warrant liability. 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 “Hercules Warrant”) to purchase 58,823 shares of common stock at an exercise price of $11.00 per share, subject to adjustment. The Hercules Warrant expires on June 30, 2020. See Note 10, “Warrants and Derivative Liabilities”, for a discussion on the Hercules Warrant and the valuation assumptions used. Under Term Loan B, the total debt discount including the Hercules 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 Term Loan B using the effective interest method. During each of the three months ended June 30, 2016 and 2015, the Company recorded non-cash interest expense for amortization of the debt discount related to the Term Loan B of less than $0.1 million. Under Term Loan C, the total debt discount, including the Hercules 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 Term Loan C using the effective interest method. During each of the three months ended June 30, 2016 and 2015, the Company recorded non-cash interest expense for amortization of the debt discount related to the Term Loan C of less than $0.1 million. 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 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 June 30, 2016, 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. Interest expense on the Term Loans for the three months ended June 30, 2016 and 2015, was $0.2 million and $0.3 million, respectively, each of which included less than $0.1 million of non-cash interest expense related to the amortization of the debt discount on the respective Term Loans. Although the Company believes that it is in compliance with the covenants and restrictions under the Term Loans as of June 30, 2016, there can be no assurance that the Company will continue to be in compliance.

Debt

Senior Secured Term Loans

On November 15, 2013, the Company amended its existing Loan and Security Agreement with Hercules and entered into a new term loan (the “Term Loan B”), borrowing $10.0 million. After closing fees and expenses, the net proceeds to the Company for the Term Loan B were $9.8 million. The Term Loan B bears an interest rate of 11% plus the percentage, if any, by which the prime rate as reported by the Wall Street Journal exceeds 3.75%. The Company is repaying the Term Loan B in equal monthly installments ending on November 1, 2016. The principal balance of the Term Loan B is approximately $1.7 million as of June 30, 2016. The Company will pay an end of term fee of $0.5 million upon the earlier of maturity or prepayment of the Term Loan B. The Company has accrued the end of term fee and recorded a corresponding amount into the debt discount. The 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 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 at inception of the loan, which have been recorded as a debt discount.

On December 19, 2014, the Company entered into a second amendment with Hercules (the “Hercules Second Amendment”) and entered into a new term loan, borrowing an additional $1.5 million (the “Term Loan C”). After closing fees and expenses, the net proceeds to the Company for the Term Loan C were $1.4 million. The Term Loan B and Term Loan C are collectively referred to as the “Term Loans”. The Term Loan C also bears the same interest rate as the Term Loan B. 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 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. The Company will pay an end of term fee of approximately $0.1 million upon earlier of maturity or prepayment of the Term Loan C. The Company has accrued the end of term fee and recorded a corresponding amount in the debt discount. The Term Loan C includes the same mandatory prepayment feature as the 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 at inception of the loan, which have been recorded as a debt discount.

Hercules received warrants to purchase 13,927 shares of common stock (the “First Warrant”) and 25,641 shares of common stock (the “Second Warrant”) in conjunction with a prior term loan which has been repaid in full and the Term Loan B. Due to certain adjustment provisions within the warrants, they qualified for liability accounting. The fair value of the warrants, $0.4 million and $0.2 million, respectively, was recorded upon issuance to debt discount and a warrant liability. 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 “Hercules Warrant”) to purchase 58,823 shares of common stock at an exercise price of $11.00 per share, subject to adjustment. The Hercules Warrant expires on June 30, 2020. See Note 10, “Warrants and Derivative Liabilities”, for a discussion on the Hercules Warrant and the valuation assumptions used.

Under Term Loan B, the total debt discount including the Hercules 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 Term Loan B using the effective interest method. During each of the three months ended June 30, 2016 and 2015, the Company recorded non-cash interest expense for amortization of the debt discount related to the Term Loan B of less than $0.1 million. Under Term Loan C, the total debt discount, including the Hercules 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 Term Loan C using the effective interest method. During each of the three months ended June 30, 2016 and 2015, the Company recorded non-cash interest expense for amortization of the debt discount related to the Term Loan C of less than $0.1 million.

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 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 June 30, 2016, 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.

Interest expense on the Term Loans for the three months ended June 30, 2016 and 2015, was $0.2 million and $0.3 million, respectively, each of which included less than $0.1 million of non-cash interest expense related to the amortization of the debt discount on the respective Term Loans.

Although the Company believes that it is in compliance with the covenants and restrictions under the Term Loans as of June 30, 2016, there can be no assurance that the Company will continue to be in compliance.