7. Equipment Financings

The Company leases certain laboratory equipment under arrangements accounted for as capital leases and classified as equipment financings. The financed equipment is depreciated on a straight-line basis over periods ranging from approximately 3 to 7 years. The total gross value of fixed assets capitalized under such financing arrangements was approximately $2,295,000 and $2,526,000 at December 31, 2017 and September 30, 2018, respectively. Total accumulated depreciation related to financed equipment was approximately $759,000 and $1,030,000 at December 31, 2017 and September 30, 2018, respectively. Total depreciation expense related to financed equipment during the three months ended September 30, 2017 and 2018 was approximately $52,000 and $115,000, respectively, and was approximately $160,000 and $271,000 during the nine months ended September 30, 2017 and 2018, respectively.

The following schedule sets forth the remaining future minimum lease payments outstanding under financed equipment arrangements, as well as corresponding remaining sales tax and maintenance obligation payments that are expensed as incurred and due within each respective year ending December 31, as well as the present value of the total amount of the remaining minimum lease payments, as of September 30, 2018:

				Maintenance
	Minimum			and Sales Tax
	Lease			Obligation
	Payments			Payments
2018 (remaining three months)	$	154,538		$	30,237
2019		613,448			88,599
2020		464,152			67,752
2021		303,228			53,252
2022		262,974			53,493
Thereafter		262,952			40,641
Total payments		2,061,292			333,974
Less amount representing interest		(473,166	)		—
Present value of payments	$	1,588,126		$	333,974

The aggregate weighted average effective annual interest rate associated with equipment financings was 13.51% and 12.53% at December 31, 2017 and September 30, 2018, respectively, and the maturity dates on such outstanding arrangements range from February 2019 to September 2024. During the three months ended September 30, 2017 and 2018, total interest expense related to equipment financings of approximately $38,000 and $60,000, respectively, was recorded to the Company’s unaudited condensed statements of operations and comprehensive loss, and approximately $118,000 and $168,000 was recorded during the nine months ended September 30, 2017 and 2018, respectively. At September 30, 2018, the present value of minimum lease payments due within one year was approximately $572,000.