Consolidated Statements of Income - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Total revenues	$ 38,187,755	$ 32,961,443
Costs and expenses:
Research and development	590,331	756,776
General and administrative	9,285,372	8,805,989
Total costs and expenses	9,875,703	9,562,765
Operating income	28,312,052	23,398,678
Other income:
Interest income	1,986,855	1,294,651
Other (expense)	(259)
Other income		103,948
Total other income	1,986,596	1,398,599
Income before income tax	30,298,648	24,797,277
Income tax provision	(5,828,840)	(4,744,008)
Net income	$ 24,469,808	$ 20,053,269
Earnings per common share:
Basic (in dollars per share)	$ 3.35	$ 2.77
Diluted (in dollars per share)	$ 3.33	$ 2.73
Shares used in calculation of net income per common share:
Basic (in shares)	7,315,144	7,242,212
Diluted (in shares)	7,351,385	7,333,368
Royalties [Member]
Revenues:
Total revenues	$ 38,187,755	$ 32,921,764
Licensing Revenue [Member]
Revenues:
Total revenues	$ 0	$ 39,679