	December 31, 2018
	Principal			Unamortized Discount			Net Carrying Value
Loan and Security Agreement	$	30,000		$	(130	)	$	29,870
Less: debt - current		(7,857	)		—			(7,857	)
Debt - non-current	$	22,143		$	(130	)	$	22,013

Debt at December 31, 2017, consisted of the following (in thousands):

	December 31, 2017
	Principal		Unamortized Discount			Total
Loan and Security Agreement	$	30,000	$	(202	)	$	29,798
Less: debt - current		—		—			—
Debt - non-current	$	30,000	$	(202	)	$	29,798

Expected future principal and interest payments based on debt balances at December 31, 2018, are expected to be as follows:

Year ended December 31,	Principal		Interest		Total
2019	$	7,857	$	2,579		10,436
2020		8,571		1,765		10,336
2021		8,572		931		9,503
2022		5,000		2,560		7,560
Total	$	30,000	$	7,835	$	37,835

Prior to December 31, 2016, the Company maintained a five-year loan and security agreement (the “Term Loan Agreement”) with Oxford Finance LLC (“Oxford”), under which the Company borrowed $20.0 million. The borrowings were set to mature on June 1, 2019, with various interest only periods.

On April 27, 2017, the Term Loan Agreement was amended to include an additional interest-only period under the Term Loan Agreement. As amended, the Company was required to make interest only payments from May 2017 through December 2017, followed by eighteen months of equal principal and interest payments thereafter. The Company was also required to make a final payment equal to 7% of the principal amounts drawn payable on the earlier to occur of maturity or prepayment.

On July 31, 2017 (the “Closing Date”), the Company entered into an amended and restated loan and security agreement (the “Amended Credit Agreement”) with Oxford, which amended and restated the Term Loan Agreement in its entirety. The Amended Credit Agreement provided for secured growth capital term loans of up to $40.0 million (the “2017 Term Loans”). All of the Company’s current and future assets, excluding its intellectual property and 35% of the Company’s investment in Cerus Europe B.V., are secured for its borrowings under the Amended Credit Agreement. The 2017 Term Loans were available in two tranches. The first tranche of $30.0 million (“2017 Term Loan A”) was drawn by the Company on July 31, 2017, with the proceeds used in part to repay in full all of the outstanding term loans under the Term Loan Agreement of $17.6 million and the final payment of the Term Loan Agreement of $1.4 million. The availability of the second tranche of $10.0 million (“2017 Term Loan B”) expired on May 14, 2018, and the Company did not elect to draw the 2017 Term Loan B. The 2017 Term Loan A bears interest at a rate equal to the greater of (i) 8.01% and (ii) the three-month U.S. LIBOR rate plus 6.72%. The interest rate on the 2017 Term Loan A at December 31, 2018 was approximately 9.53%. The Company will also be required to make a final payment fee of 8.00% of the principal amounts of the 2017 Term Loan A. The Amended Credit Agreement contains certain nonfinancial covenants, with which the Company was in compliance at December 31, 2018.