Condensed Consolidated Balance Sheets (unaudited) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 17,597,430	$ 13,176,452
Short term investments	66,899,660	67,707,143
Accounts receivable	16,476,790	16,518,687
Deferred royalty buy-down	0	184,931
Prepaid expenses and other current assets	604,392	646,749
Total current assets	101,578,272	98,233,962
Long-term investments	3,635,115	1,099,834
Deferred tax assets, net	313,768	313,768
Patent costs, net	425,678	444,478
Total assets	105,952,833	100,092,042
Current liabilities:
Accounts payable and accrued expenses	1,944,663	1,798,588
Income tax payable	1,802,847	704,934
Total current liabilities	3,747,510	2,503,522
Commitments and Contingencies
Stockholders' equity:
Common stock, $.001 par value; 10,000,000 shares authorized; 7,740,167 and 7,738,167 shares issued, 7,277,902 and 7,275,902 shares outstanding as of March 31, 2019 and December 31, 2018, respectively	7,740	7,738
Additional paid-in capital	36,502,652	36,302,446
Retained earnings	76,593,314	72,176,719
Treasury stock, 462,265 shares at cost as of March 31, 2019 and December 31, 2018	(10,898,383)	(10,898,383)
Total stockholders' equity	102,205,323	97,588,520
Total liabilities and stockholders' equity	105,952,833	100,092,042
Series A Preferred Stock [Member]
Stockholders' equity:
Series A Preferred stock, $.50 par value, 700,000 shares authorized; none outstanding	$ 0	$ 0