Condensed Consolidated Balance Sheets (unaudited) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 13,972,558	$ 13,176,452
Short term investments	71,304,188	67,707,143
Accounts receivable	16,729,636	16,518,687
Deferred royalty buy-down	0	184,931
Prepaid expenses and other current assets	1,012,172	646,749
Total current assets	103,018,554	98,233,962
Long-term investments	8,233,138	1,099,834
Deferred tax assets, net	154,309	313,768
Patent costs, net	493,856	444,478
Total assets	111,899,857	100,092,042
Current liabilities:
Accounts payable and accrued expenses	710,812	1,798,588
Income tax payable	878,624	704,934
Total current liabilities	1,589,436	2,503,522
Commitments and Contingencies
Stockholders' equity:
Common stock, $.001 par value; 10,000,000 shares authorized 7,796,230 and 7,738,167 shares issued, 7,331,917 and 7,275,902 shares outstanding as of June 30, 2019 and December 31, 2018, respectively	7,796	7,738
Additional paid-in capital	38,299,800	36,302,446
Retained earnings	83,019,774	72,176,719
Treasury stock, 464,313 and 462,265 shares at cost as of June 30, 2019 and December 31, 2018, respectively	(11,016,949)	(10,898,383)
Total stockholders' equity	110,310,421	97,588,520
Total liabilities and stockholders' equity	111,899,857	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