Condensed Consolidated Balance Sheets - USD ($)	Mar. 31, 2020	Dec. 31, 2019
CURRENT ASSETS
Cash and cash equivalents	$ 7,230,330	$ 7,358,856
Short-term investments	1,727,483	1,222,053
Short-term investments - other	2,400,000	2,600,000
Accounts receivable, net	4,410,935	5,597,701
Inventories, net (note 3)	8,815,111	9,571,807
Prepaid expenses and other current assets	1,398,596	1,672,422
Income tax receivable	0	77,385
Total Current Assets	25,982,455	28,100,224
LONG-TERM ASSETS
Long-term investments	6,552,150	7,399,963
Financing right-of-use asset	88,035	107,991
Property and equipment, net	11,913,754	12,071,019
Intangible assets, net	1,938,919	1,989,782
Goodwill	2,579,381	2,579,381
Total Long-Term Assets	23,072,239	24,148,136
TOTAL ASSETS	49,054,694	52,248,360
CURRENT LIABILITIES
Accounts payable	1,460,159	2,633,520
Accrued liabilities (note 4)	1,296,997	2,089,391
Current financing lease liability (note 5)	50,067	59,376
Income taxes payable	439,592	403,092
Total Current Liabilities	3,246,815	5,185,379
LONG-TERM LIABILITIES
Net deferred income tax liability	324,711	439,275
Long-term financing lease liability (note 5)	40,761	52,120
TOTAL LIABILITIES	3,612,287	5,676,774
STOCKHOLDERS' EQUITY (note 6)
Preferred stock: $0.001 par value, 10,000,000 shares authorized: no shares issued or outstanding	0	0
Common stock: $0.001 par value, 100,000,000 shares authorized: 51,098,039 issued and 47,685,661 outstanding at March 31, 2020, and 50,824,355 issued and 47,411,977 outstanding at December 31, 2019	51,098	50,824
Treasury stock, at cost	(5,353,019)	(5,353,019)
Additional paid-in capital	29,922,760	29,584,172
Accumulated other comprehensive loss	(3,518,237)	(2,415,460)
Retained earnings	24,339,805	24,705,069
TOTAL STOCKHOLDERS' EQUITY	45,442,407	46,571,586
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 49,054,694	$ 52,248,360
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	51,098,039	50,824,355
Common stock, shares outstanding (in shares)	47,685,661	47,411,977