Pursuant to the Company’s asset purchase agreement with NuvoGen Research, LLC (“NuvoGen”), as amended, the Company is obligated to pay NuvoGen the greater of $400,000 or 6% of annual revenue until the obligation is paid in full. In addition to fixed quarterly payments of $100,000, there were $24,452 of revenue-based payments payable as of June 30, 2021, compared with approximately $54,777 of revenue-based payments payable as of December 31, 2020. There have been no significant modifications to the terms and conditions of the Company’s NuvoGen obligation since the disclosures made in Part II, Item 8, Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K, filed with the SEC on March 25, 2021.

Remaining minimum payments to be made in 2021 include $24,452 of revenue-based payments payable as of June 30, 2021 and an estimate of additional revenue-based payments to be made in the fourth quarter of 2021 relating to actual revenue generated in the third quarter of 2021, estimated using actual revenue generated in the same quarter in 2020. Minimum payments for 2022 include an estimate of additional revenue-based payments to be made in the first and second quarters of 2022 relating to revenue generated in the fourth quarter of 2021 and the first quarter of 2022, estimated using actual revenue generated in the same quarters in 2020 and 2021. Remaining minimum payments include only the minimum quarterly payments to be made in each period. Actual payments could vary from what is shown in the table, to the extent that 6% of the Company’s annual revenue in 2021 and beyond exceeds $400,000.

The remaining minimum payments to be made to NuvoGen as of June 30, 2021 are as follows for each fiscal year:

2021	$	231,078
2022		454,980
2023		400,000
2024		400,000
2025		400,000
2026 and beyond		2,771,713
Total NuvoGen obligation payments		4,657,771
Plus interest accretion		73,226
Total NuvoGen obligation, net	$	4,730,997

The Company has recorded the obligation at the estimated present value of the future payments using a discount rate of 2.5%, the Company’s estimate of its effective borrowing rate for similar obligations. The unamortized interest accretion was $(73,226) and $(79,376) as of June 30, 2021 and December 31, 2020, respectively. Discount accreted during the three and six months ended June 30, 2021 was $(3,043) and $(6,149), respectively, compared with $(3,226) and $(6,656) for the three and six months ended June 30, 2020, respectively.