Condensed Consolidated Income Statements (unaudited) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues:
Total Revenues	$ 9,442,253	$ 8,168,081	$ 26,424,380	$ 23,108,264
Costs and expenses:
Research and development	143,185	162,625	454,042	569,648
General and administrative	1,978,078	2,232,077	6,613,362	6,345,662
Total Cost and Expenses	2,121,263	2,394,702	7,067,404	6,915,310
Operating income	7,320,990	5,773,379	19,356,976	16,192,954
Other income:
Interest income	504,909	359,637	1,471,489	851,334
Other income	0	0	0	96,663
Total other income	504,909	359,637	1,471,489	947,997
Income before income tax expense	7,825,899	6,133,016	20,828,465	17,140,951
Provision for income tax expense	(1,552,966)	(1,089,966)	(3,712,477)	(3,271,366)
Net income	$ 6,272,933	$ 5,043,050	$ 17,115,988	$ 13,869,585
Basic net income per share (in dollars per share)	$ 0.86	$ 0.69	$ 2.34	$ 1.92
Diluted net income per share (in dollars per share)	$ 0.85	$ 0.69	$ 2.33	$ 1.89
Shares used in computation of basic net income per share (in shares)	7,334,212	7,281,388	7,306,665	7,230,106
Shares used in computation of diluted net income per share (in shares)	7,359,034	7,356,885	7,347,701	7,327,029
Royalties [Member]
Revenues:
Total Revenues	$ 9,442,253	$ 8,168,081	$ 26,424,380	$ 23,068,585
Licensing Revenues [Member]
Revenues:
Total Revenues	$ 0	$ 0	$ 0	$ 39,679