Consolidated Balance Sheets - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 4,999,183	$ 13,176,452
Short term investments	84,239,918	67,707,143
Accounts receivable	19,065,919	16,518,687
Deferred royalty buy-down	0	184,931
Prepaid expenses and other current assets	966,456	646,749
Total current assets	109,271,476	98,233,962
Long-term investments	16,569,024	1,099,834
Deferred tax assets, net	0	313,768
Operating lease right-of-use asset	239,491	0
Patent costs, net	573,277	444,478
Total assets	126,653,268	100,092,042
Current liabilities:
Accounts payable and accrued expenses	998,409	1,798,588
Income tax payable	354,984	704,934
Current portion of lease obligation	69,099	0
Total current liabilities	1,422,492	2,503,522
Lease obligation	167,014	0
Deferred tax liability, net	572,660	0
Commitments and contingencies (Note 10)
Stockholders' equity:
Common stock, $.001 par value; 10,000,000 shares authorized; 7,813,230 and 7,738,167 shares issued, 7,339,578 and 7,275,902 outstanding at December 31, 2019 and 2018, respectively	7,813	7,738
Additional paid-in capital	39,355,797	36,302,446
Retained earnings	96,646,527	72,176,719
Treasury stock, 473,652 and 462,265 shares at cost as of December 31, 2019 and 2018	(11,519,035)	(10,898,383)
Total stockholders' equity	124,491,102	97,588,520
Total liabilities and stockholders' equity	126,653,268	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