	As of December 31,
	2020			2019
2018 Notes	$	24,972		$	24,270
Payroll protection plan		3,107		—
Convertible notes payable	—				13,159
Unamortized debt discount and debt issuance costs		(313	)		(1,458	)
		27,766			35,971
Less: current maturities		11,840			12,159
Long-term notes payable	$	15,926		$	23,812

In February 2018, the Company issued long-term debt of $23.0 million to Innovatus Life Sciences Lending Fund (Innovatus or Lender) (the 2018 Notes). Innovatus is also a holder of the Company’s common stock.

At the time of issuance, the Company paid a facility fee of $0.2 million and issued a warrant to Innovatus, with an initial estimated fair value of $0.3 million, for the purchase of 613,333 shares of Series G preferred stock. The facility fee and the estimated warrant fair value were recorded as debt discount and is amortized to interest expense over the term of the 2018 Notes. The 2018 Notes bear annual interest at 10%, of which 7.5% is payable in cash, with the remaining 2.5% added to principal through December 31, 2020. Total interest added to principal was $1.7 million and $1.1 million as of December 31, 2020 and 2019, respectively. Commencing March 2021 and continuing through the maturity date February 2023, the outstanding principal is repayable in 24 equal monthly installments.

The loan may be prepaid by the Company at any time, subject to a prepayment penalty of up to 3% of the principal amount, depending on the date of prepayment. Upon payment of the 2018 Notes at maturity or prepayment on any earlier date, unless waived, a 2% back-end facility fee will apply to the amounts paid or prepaid. The 2% fee is recognized as additional interest expense over the loan term. The 2018 Notes are senior to all of the Company’s other indebtedness including any contingent consideration payable to Indi.

The 2018 Notes contain customary affirmative covenants, and contain negative covenants limiting the ability of the Company to, among other things, incur future debt, transfer assets except for the ordinary course of business, make acquisitions, make certain restricted payments, or to sell assets, subject to certain exceptions. In addition, the 2018 Notes require the Company to comply with a minimum daily liquidity covenant and a rolling monthly revenue requirement. Failure to comply with the covenants and loan requirements may result in early amortization of the loan in a 24- or 36-month payment schedule. As of December 31, 2020, the Company was in compliance with all terms and covenants.

The Company granted the Lender a security interest in all of the Company’s assets through a pledge and security agreement, patent security agreement and trademark security agreement, each between the Company and the Lender.

In April 2020, the Company entered into a loan pursuant to the Paycheck Protection Program under the CARES Act, as administered by the U.S. Small Business Administration (the SBA). The loan, in the principal amount of $3.1 million (the PPP Loan), was disbursed by JPMorgan Chase Bank (JPM) pursuant to a Paycheck Protection Program Promissory Note and Agreement (the Note and Agreement).

The PPP Loan matures on the two-year anniversary of the funding date, April 2022, and bears interest at a fixed rate of 1.00% per annum. Monthly principal and interest payments, less the amount of any potential forgiveness (as discussed below), will commence in September 2021. The Company did not provide any collateral or guarantees in connection with the PPP Loan, nor did the Company pay any facility charge to obtain the PPP Loan. The Note and Agreement provides for customary events of default, including those relating to failure to make payment, bankruptcy, breaches of representations and material adverse effects. The Company may prepay the principal of the PPP Loan at any time without incurring any prepayment charges.

All or a portion of the PPP Loan may be forgiven by the SBA and JPM upon application by the Company. Under the CARES Act, loan forgiveness is available for the sum of documented payroll costs, covered rent payments, and covered utilities during the eight-week period beginning on the approval date of the PPP Loan. For purposes of the CARES Act, payroll costs exclude compensation of an individual employee earning more than $100,000, prorated annually. Not more than 40% of the forgiven amount may be for non-payroll costs. Forgiveness is reduced if full-time headcount declines, or if salaries and wages for employees with salaries of $100,000 or less annually are reduced by more than 25%. The Company currently intends to repay the PPP loan in accordance with the underlying terms and conditions. To the extent we elect to seek forgiveness, the Company cannot assure that the PPP Loan will be forgiven, in whole or in part. If the loan is forgiven in part or in whole, and legal release is received, the Company will reduce the liability by the amount forgiven and record a gain on extinguishment in the statements of operations.

In March 2020, the Company issued $10.0 million of convertible notes primarily to existing stockholders that were originally scheduled to mature in August 2020 (the March 2020 Notes). In August 2020, the Company and its lenders agreed to extend the maturity date to June 30, 2021. The March 2020 Notes were issued in two tranches of $5.0 million, with the first in March 2020 and the second in June 2020. Interest on the March 2020 Notes was 3% per annum, payable in full upon maturity through conversion to Series H Preferred Stock at 80% of the original issuance price of $1.15 per share. Under the terms of the March 2020 Notes, on or before the maturity date and if the March 2020 Notes are unpaid, the outstanding principal and unpaid accrued interest under the March 2020 Notes shall be automatically converted into common stock in an initial public offering at a conversion price of 80% of the per share price of common stock sold in the initial public offering. The discount on the automatic conversion was separated from the March 2020 Notes and reported as a debt discount and put option liability of $2.5 million and was amortized over the term of the March 2020 Notes. Following the closing of the initial public offering in October 2020, the March 2020 Notes were automatically converted into 703,503 shares of common stock at a conversion price of $14.40, or 80% of the initial public offering price per common share.

In December 2019, the Company issued $6.0 million of convertible notes primarily to existing preferred shareholders that were originally scheduled to mature in August 2020 (the December 2019 Notes). In August 2020, the Company and its lenders agreed to extend the maturity date to June 30, 2021. The December 2019 Notes were issued in two tranches of $3.0 million, the first in December 2019 and the second in February 2020. Interest on the December 2019 Notes was 3% per annum and payable in full upon maturity through the conversion to Series H Preferred Stock at 80% of the original issuance price of $1.15 per share. Under the terms of the December 2019 Notes, on or before the maturity date and if the December 2019 Notes are unpaid, the outstanding principal and unpaid accrued interest under the December 2019 Notes shall be automatically converted into common stock in an initial public offering at a conversion price of 80% of the per share price of common stock sold in the initial public offering. The discount on the automatic conversion was separated from the December 2019 Notes and reported as a debt discount and put option liability of $1.5 million and was amortized over the term of the December 2019 Notes. Following the closing of the initial public offering in October 2020, the December 2019 Notes were automatically converted into 426,386 shares of common stock at a conversion price of $14.40, or 80% of the initial public offering price per common share.

In August and September 2019 (the August 2019 Notes), the Company issued $10.0 million of convertible notes primarily to existing preferred shareholders that were originally scheduled to mature in August 2020. In August 2020, the Company and its lenders agreed to extend the maturity date to June 30, 2021. Interest on the August 2019 Notes was 3% per annum and payable in full upon maturity through the conversion to Series H Preferred Stock at 95% of the original issuance price of $1.15 per share. Under the terms of the August 2019 Notes, on or before the maturity date and if the August 2019 Notes are unpaid, the outstanding principal and unpaid accrued interest under the August 2019 Notes shall be automatically converted into common stock in an initial public offering at a conversion price of 95% of the per share price of common stock sold in the initial public offering. In connection with the issuance of the December 2019 Notes, the conversion price on the August 2019 Notes was amended to 80%. The initial discount on the automatic conversion created an initial put option liability of $0.5 million that was separated from the August 2019 Notes. The amendment to the conversion price of the August 2019 Notes in December 2019 resulted in an increase to the put option liability of $2.0 million to a total estimated value of $2.5 million as of December 31, 2019. The increase in the value of the put option liability was reflected as a change in put option in the 2019 statement of operations. Following the closing of the initial public offering in October 2020, the August 2019 Notes were automatically converted into 718,391 shares of common stock at a conversion price of $14.40, or 80% of the initial public offering price per common share.

Scheduled principal repayments (maturities) of long-term obligations as of December 31, 2020 were as follows (in thousands):

Year Ending December 31,	As of December 31, 2020
2021	$	11,840
2022		13,919
2023		2,320
2024		—
2025		—
Thereafter	—
	$	28,079