Consolidated Statements of Income - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues:
Royalties	$ 20,800,757	$ 12,985,370	$ 11,767,758
Licensing revenue	1,949,378	1,059,254	2,662,024
Total revenues	22,750,135	14,044,624	14,429,782
Costs and expenses:
Research and development	1,034,288	1,263,512	1,484,416
General and administrative	7,272,532	5,814,185	5,038,363
Total costs and expenses	8,306,820	7,077,697	6,522,779
Operating income	14,443,315	6,966,927	7,907,003
Other income:
Interest income	92,926	32,158	26,202
Other	14,719	33,582	37,458
Total other income (expense)	107,645	65,740	63,660
Income before income tax	14,550,960	7,032,667	7,970,663
Income tax provision	(4,933,328)	(2,386,707)	(2,684,816)
Net income	$ 9,617,632	$ 4,645,960	$ 5,285,847
Earnings per common share:
Basic (in dollars per share)	$ 1.41	$ 0.72	$ 0.83
Diluted (in dollars per share)	$ 1.32	$ 0.66	$ 0.76
Shares used in calculation of net income per common share:
Basic (in shares)	6,827,355	6,477,457	6,345,615
Diluted (in shares)	7,272,989	7,079,570	6,922,274