Condensed Consolidated Statements of Cash Flows - USD ($)	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Operating activities
Net loss	$ (12,385,728)	$ (7,463,259)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	353,269	375,334
Accretion of discount on NuvoGen obligation	(5,850)	(6,149)
Provision for excess inventory	157,409	5,507
Amortization of SVB Term Loan discount and issuance costs	227,303	234,927
Stock-based compensation expense	465,956	677,194
Employee stock purchase plan expense	33,183	26,231
Non-cash operating lease expense	202,091	254,584
Accrued interest on available-for-sale securities investments	(218)	(10,530)
Gain on forgiveness of PPP Loan	0	(1,735,792)
(Gain) loss on abandonment and disposal of assets, net	(4,000)	178,925
Changes in operating assets and liabilities:
Accounts receivable	833,373	(114,735)
Inventory	(232,328)	(831,511)
Prepaid expenses and other	1,104	(573,569)
Accounts payable	(544,368)	443,816
Accrued liabilities	(676,855)	(117,926)
Contract liabilities	(11,114)	21,241
Operating lease liabilities	(202,331)	(266,464)
Net cash used in operating activities	(11,789,104)	(8,902,176)
Investing activities
Purchase of property and equipment	(15,078)	(241,474)
Gain on sales of property and equipment	4,000
Maturities of available-for-sale securities	11,600,000	6,300,000
Purchase of available-for-sale securities	(7,610,724)	(16,173,223)
Net cash (used in) provided by investing activities	3,978,198	(10,114,697)
Financing activities
Proceeds from ATM Offering, net of commissions of $0.3 million		10,665,819
Proceeds from March 2022 Purchase Agreement, net of $0.4 million of issuance costs	7,073,950
Payments on NuvoGen obligation	(272,624)	(254,979)
Payments on SVB Term Loan	(2,500,000)
Payments on deferred offering costs	(67,845)
Payments on financing leases	(9,082)	(12,694)
Proceeds from exercise of stock options		326
Taxes paid for net share settlement of restricted stock awards	(10,014)	(1,892)
Proceeds from shares purchased under stock purchase plans	23,327	53,437
Proceeds from exercise of pre-funded warrants	2,411
Payments on insurance notes	(258,011)	(247,047)
Net cash provided by financing activities	3,982,112	10,202,970
Effect of exchange rates on cash	(14,578)	(7,464)
Decrease in cash and cash equivalents	(3,843,372)	(8,821,367)
Cash and cash equivalents at beginning of period	9,599,950	22,397,812
Cash and cash equivalents at end of period	5,756,578	13,576,445
Supplemental disclosure of noncash investing and financing activities
Fixed asset purchases payable and accrued at period end		41,864
Issuance of common stock upon conversion of Series A convertible preferred stock	1,402,430
Issuance of common stock from cashless exercise of pre-funded warrants		145
Deferred financing costs payable and accrued at period end	15,616
2022 and 2021 Insurance Notes issued for insurance premiums	822,889	746,360
Gain on forgiveness of PPP Loan		1,735,792
Reclassification of refund liability to accounts receivable		281,722
Supplemental cash flow information
Cash paid for interest	272,920	296,835
Cash paid for taxes	$ 5,399	$ 12,665