Consolidated Balance Sheets - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 13,176,452	$ 7,333,810
Short term investments	67,707,143	51,973,971
Accounts receivable	16,518,687	4,655,105
Deferred royalty buy-down	184,931	1,794,126
Prepaid expenses and other current assets	646,749	623,503
Total current assets	98,233,962	66,380,515
Long-term investments	1,099,834	5,745,974
Deferred royalty buy-down - long term, net	0	732,206
Deferred tax assets, net	313,768	1,739,706
Patent costs, net	444,478	397,993
Total assets	100,092,042	74,996,394
Current liabilities:
Accounts payable and accrued expenses	1,798,588	933,998
Income tax payable	704,934	68,733
Deferred revenue	0	1,057,979
Accrued liabilities of discontinued operations	0	78,138
Total current liabilities	2,503,522	2,138,848
Long-term deferred revenue	0	5,340,708
Commitments and contingencies (Note 10)
Stockholders' equity:
Common stock, $.001 par value; 10,000,000 shares authorized; 7,738,167 and 7,600,167 shares issued, 7,275,902 and 7,189,233 outstanding at December 31, 2018 and 2017, respectively	7,738	7,600
Additional paid-in capital	36,302,446	33,468,323
Retained earnings	72,176,719	41,939,115
Treasury stock, 462,265 and 410,934 shares at cost as of December 31, 2018 and 2017	(10,898,383)	(7,898,200)
Total stockholders' equity	97,588,520	67,516,838
Total liabilities and stockholders' equity	100,092,042	74,996,394
Series A Preferred Stock [Member]
Stockholders' equity:
Series A Preferred stock, $.50 par value, 700,000 shares authorized; none outstanding	$ 0	$ 0