Condensed Consolidated Balance Sheets (Unaudited) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 397,713	$ 771,757
Restricted cash	800,000	800,000
Accounts receivable, net of allowance of doubtful accounts of $173,603 as of March 31, 2021 and December 31, 2020	8,646,020	9,203,334
Inventories, net	17,984,073	16,504,840
Prepaid expenses and other current assets	402,743	399,119
Total current assets	28,230,549	27,679,050
Equipment, net	646,265	455,066
Operating lease right-of-use assets, net	68,032	86,948
Goodwill	58,872	58,872
Intangible assets, net	360,963	388,629
Other assets	974,021	942,404
Total assets	30,338,702	29,610,969
Current liabilities
Bank credit line	6,918,783	2,442,246
Accounts payable	10,049,107	11,744,834
Current maturities of government loan	60,470	65,225
Current maturities of operating lease liabilities	60,368	65,651
Accrued other expenses	4,947,257	7,465,063
Deferred revenue, current	110,218	0
Total current liabilities	22,146,203	21,783,019
Long term government loan, less current maturities	0	15,245
Operating lease liabilities, less current maturities	9,005	22,235
Deferred revenue noncurrent	154,679	0
Total liabilities	22,309,887	21,820,499
Commitments and Contingencies (Note 6)
Stockholders' equity
Common stock: Authorized: 40,000,000 shares at $0.01 par value; issued and outstanding: 35,362,854 shares at March 31, 2021 and 35,074,922 shares at December 31, 2020, respectively	353,628	350,749
Additional paid-in capital	65,307,650	64,526,664
Accumulated deficit	(57,632,463)	(57,086,943)
Total stockholders' equity	8,028,815	7,790,470
Total liabilities and stockholders' equity	$ 30,338,702	$ 29,610,969