Condensed Consolidated Statements of Cash Flows - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities
Net loss	$ (5,457,898)	$ (5,370,846)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	348,633	308,984
Accretion of discount on NuvoGen obligation	(3,430)	(3,414)
Provision for excess inventory	6,947	24,296
Amortization of QNAH Convertible Note issuance costs	3,364	3,364
Amortization of MidCap Credit Facility discount and issuance costs	42,441	39,143
Stock-based compensation expense	415,292	241,246
Employee stock purchase plan expense	5,379	16,794
Amortization of operating lease right-of-use assets	151,726	72,923
Accrued interest on available-for-sale securities investments	(74,101)	(72,698)
Loss on abandonment of assets	49,226
Changes in operating assets and liabilities:
Accounts receivable	1,961,707	1,662,828
Inventory	(375,178)	103,272
Prepaid expenses and other	139,508	9,777
Deferred offering costs	140,320
Accounts payable	(410,806)	(480,546)
Accrued liabilities	(668,667)	(1,977,373)
Contract liabilities	(18,794)	(55,246)
Operating lease liabilities	(186,220)	(115,440)
Net cash used in operating activities	(3,930,551)	(5,592,936)
Investing activities
Purchase of property and equipment	(25,231)	(103,316)
Sales, redemptions and maturities of available-for-sale securities	8,250,000	12,800,000
Purchase of available-for-sale securities	(4,272,298)	(8,099,573)
Net cash provided by investing activities	3,952,471	4,597,111
Financing activities
Proceeds from ATM Offering, net	2,435,912
Proceeds from Series A convertible preferred stock in private placement	600,030
Proceeds from exercise of pre-funded warrants	31,768
Payments on NuvoGen obligation	(287,997)	(463,686)
Payments on financing leases	(11,833)	(13,782)
Proceeds from exercise of stock options		51,570
Taxes paid for net share settlement of restricted stock awards	(7,052)	(9,685)
Payment of deferred offering costs		(30,175)
Net cash provided by (used in) financing activities	2,760,828	(465,758)
Effect of exchange rates on cash	1,201	4,063
Increase (decrease) in cash, cash equivalents and restricted cash	2,783,949	(1,457,520)
Cash, cash equivalents and restricted cash at beginning of period	10,889,995	11,702,847
Cash, cash equivalents and restricted cash at end of period	13,673,944	10,245,327
Supplemental disclosure of noncash investing and financing activities
Fixed asset purchases payable and accrued at period end	289,838	13,945
Adoption of ASC 842, Leases		694,352
Deferred offering costs payable and accrued at period end		108,883
Issuance of Series A convertible preferred stock in exchange for outstanding common stock	2,424,900
Series A convertible preferred stock in private placement, costs payable and accrued at period end	37,075
Issuance of common stock in connection with LP Purchase Agreement	615
LP Purchase Agreement, costs payable and accrued at period end	96,000
Supplemental cash flow information
Cash paid for interest	$ 164,005	$ 172,032