Debt

On January 15, 2018, the Company and Hercules Technology Growth Capital Limited (“Hercules”) amended its loan agreement so that amortization payments due for the thirteen (13) consecutive months commencing on December 1, 2017 through and including December 1, 2018 were deferred. Commencing on January 1, 2019, and continuing on the first business day of each month thereafter, the loan, including the deferred payments, shall begin amortizing in equal monthly installments of principal and interest based upon an amortization schedule equal to eighteen (18) consecutive months. Any remaining obligations under the loan agreement and other loan documents are due and payable on the maturity date on September 1, 2019.

At March 31, 2018 and December 31, 2017, the carrying value of the current and non-current portion of long-term debt is $4,879 and $4,855, respectively.

At March 31, 2018, the principal maturities of the long-term debt were as follows:



	March 31, 2018
2018	—
2019	4,999
Principal balance outstanding	4,999
less: unamortized discount	(108	)
less: unamortized debt issuance costs	(12	)
Long-term debt	4,879
Current portion	776
Noncurrent portion	4,103

The Company paid interest on debt of $136 and $153 during the three months ended March 31, 2018 and 2017, respectively.