Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net income	$ 11,372,239	$ 9,617,632	$ 4,645,960
Adjustments to reconcile net income to net cash provided in operating activities:
Amortization	1,691,539	933,009	247,097
Stock-based compensation expense	133,904	105,782	21,416
Deferred tax expense	(2,667,150)	455,799	429,005
Gain on the sale of fixed assets	0	0	(1,150)
Changes in operating assets and liabilities:
Accounts receivable	(1,262,872)	390,811	2,051,335
Income tax receivable	422,132	(263,727)	(397,408)
Prepaid expenses and other current assets	(240,535)	(124,647)	81,708
Patent costs	(23,341)	(25,934)	(198,952)
Accounts payable and accrued expenses	127,640	67,313	(90,580)
Deferred royalty buy-down	(600,000)	(600,000)	(600,000)
Deferred revenue	7,398,793	50,622	(59,255)
Net cash provided by operating activities from operations	16,352,349	10,606,660	6,129,176
Cash flows from investing activities:
Maturities of marketable securities	43,242,679	14,070,544	7,646,964
Purchases of marketable securities	(59,935,130)	(34,180,085)	(12,848,374)
Proceeds from sale of fixed assets	0	0	1,150
Net cash used in investing activities from operations	(16,692,451)	(20,109,541)	(5,200,260)
Cash flows from financing activities:
Proceeds from stock option exercises	711,400	2,823,983	2,146,821
Repurchases of common stock	(1,048,592)	(1,802,466)	(829,613)
Excess tax benefits from share-based payment arrangements	302,783	3,808,423	1,939,832
Net cash (used in) provided by financing activities from operations	(34,409)	4,829,940	3,257,040
(Decrease) increase in cash and cash equivalents	(374,511)	(4,672,941)	4,185,956
Cash and cash equivalents at beginning of year	5,137,875	9,810,816	5,624,860
Cash and cash equivalents at end of year	4,763,364	5,137,875	9,810,816
Cash paid during the period for:
Interest	0	0	0
Taxes	$ 7,945,000	$ 1,906,000	$ 415,279