7. Long-term debt

Long-term debt consisted of the following:


	March 31,		March 31,
	2021		2020

Principal amount of long-term debt	$	—	$	10,000
Unamortized debt discount		—		(199)
Long-term debt, net of discount	$	—	$	9,801

Hercules Loan Agreement

On August 8, 2019, (the "Closing Date") the Company and certain of its affiliates entered into a Loan and Security Agreement (as amended, the "Hercules Loan Agreement") with Hercules Capital, Inc. ("Hercules") pursuant to which Hercules agreed to make available to the Company a secured term loan facility in the amount of $30,000 (the "Term Loan Facility"), subject to certain terms and conditions. The Company borrowed $10,000 under the Hercules Loan Agreement in one advance as a single tranche term Loan on the Closing Date upon which the Company paid a $225 facility charge and incurred $130 in additional closing and legal fees.

On June 1, 2020, the Company entered into the First Amendment to the Hercules Loan Agreement (the “Hercules First Amendment”), to, among other things, increase the aggregate principal amount of the secured term loan facility from $30,000 to $40,000. Pursuant to the Hercules First Amendment, subject to the achievement of certain milestones, the Company could have borrowed three tranches of up to $10,000 between October 1, 2020 and December 15, 2020, July 1, 2020 and June 30, 2021, and July 1, 2021 and December 15, 2021, respectively. The Company incurred $100 in additional closing and legal fees in connection with Hercules First Amendment which were capitalized and will be amortized as part of the effective yield.

On December 15, 2020, the Company entered into a Payoff Letter with respect to the Hercules Loan Agreement, which resulted in a loss on extinguishment of debt of $913 including both cash and non-cash expense. Pursuant to the Payoff Letter, the Company paid a total of $10,839 to Hercules, representing $10,000 in outstanding principal, $495 end of term charge, $300 early termination fee due and $44 in accrued interest owed to Hercules under the Hercules Loan Agreement. In connection with the execution of the Payoff Letter and the repayment of the Company’s outstanding obligations under the Hercules Loan Agreement, the Hercules Loan Agreement and the related loan documents were terminated.

The Term Loan Facility was secured by substantially all of the Company's assets, but excluding its intellectual property, and subject to certain exceptions and exclusions. All liens on the Company’s assets held by Hercules were released in connection with the execution of the Payoff Letter.

In connection with entering into the Hercules Loan Agreement the Company paid Hercules $355 of upfront fees, including closing costs and legal fees associated with entering into the agreement, which were recorded as a debt discount. In connection with entering into the Hercules First Amendment, the Company paid $100 of upfront fees, including closing costs and legal fees associated with entering into the amendment, which were recorded as debt discount. The debt discount is reflected as a reduction of the carrying value of long-term debt on the Company's consolidated balance sheet for the year ended March 31, 2020.

The Company recognized aggregate interest expense under the Hercules Loan Agreement of $818 and $734 during the years ended March 31, 2021 and 2020, respectively, which included non-cash interest expense of $181 and $156. Non-cash interest expense included the amortization of the debt discount of $82 and $60, and the accretion of the final payment of $99 and $96, respectively, for the years ended March 31, 2021 and 2020.

There were no principal payments due or paid under the Hercules Loan Agreement during the year ended March 31, 2021.