The Company entered into an asset purchase agreement in 2001, as amended, with NuvoGen Research, LLC (“NuvoGen”) to acquire certain intellectual property from NuvoGen. The Company accounted for the transaction as an asset acquisition. However, as the intellectual property was determined to not have an alternative future use, the upfront consideration was expensed. In exchange for the intellectual property, the Company agreed to pay total aggregate cash compensation to NuvoGen under the agreement of $15.0 million. Certain terms of the agreement were amended in November 2003, September 2004, November 2012 and February 2014.

Pursuant to the latest amendment to the agreement, the Company is obligated to pay the greater of $0.4 million or 6% of annual revenue until the obligation is paid in full. The Company paid yearly fixed fees, in quarterly installments, to NuvoGen of $0.4 million as well as revenue-based payments of $0.1 million and $0.2 million during the years ended December 31, 2021 and 2020, respectively, for the amount by which 6% of revenue exceeded the applicable fixed fee. Beginning on January 1, 2019 and continuing until the remaining obligation has been paid in full, interest on the remaining unpaid obligation is being accrued and will compound annually at a rate of 2.5% per year. Accrued interest related to this obligation is payable on the date that the remaining obligation is paid in full.

Minimum payments to be made in 2022 include $72,624 of revenue-based payments payable as of December 31, 2021 and an estimate of additional revenue-based payments to be made throughout the remainder of 2022 relating to revenue generated in the first, second and third quarters of 2022 using actual revenue generated in the same quarters in 2021. Minimum payments for the remaining years include only the minimum payments for each year. Actual payments could be significantly more than provided in the table, to the extent that 6% of the Company’s annual revenue in those years exceeds $0.4 million:

2022	$	548,301
2023		400,000
2024		400,000
2025		400,000
2026		400,000
2027 and beyond		2,233,792
Total NuvoGen obligation payments		4,382,093
Plus interest accretion		67,088
Total NuvoGen obligation, net	$	4,449,181

The Company has recorded the obligation at the estimated present value of the future payments using a discount rate of 2.5%, which represents the Company’s estimate of its effective borrowing rate for similar obligations. The unamortized interest accretion was $(67,088) and $(79,376) as of December 31, 2021 and 2020, respectively. Discount accreted during the years ended December 31, 2021 and 2020 was $(12,288), and $(12,935), respectively, and was included in interest expense in the consolidated statements of operations.