Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income	$ 5,401,839	$ 4,088,104
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization	816,113	319,582
Stock-based compensation expense	66,952	38,830
Deferred tax expense	(2,735,645)	240,628
Changes in operating assets and liabilities:
Accounts receivable	(1,731,520)	(63,244)
Income tax receivable	32,404	(55,121)
Prepaid expenses and other current assets	(346,946)	(329,256)
Patent costs	(11,215)	(17,381)
Accounts payable and accrued expenses	(23,568)	287,693
Deferred revenue	7,953,439	(24,688)
Net cash provided by operating activities	9,421,853	4,485,147
Cash flows from investing activities:
Maturity of marketable investments	21,703,040	8,302,605
Purchases of marketable investments	(28,934,178)	(16,933,286)
Net cash used in investing activities	(7,231,138)	(8,630,681)
Cash flows from financing activities:
Proceeds from stock option exercises	177,250	1,672,973
Payments for repurchase of common stock	(692,818)	(701,121)
Excess tax benefits from share-based payment arrangements	151,380	1,910,065
Net cash (used in) provided by financing activities	(364,188)	2,881,917
Increase (decrease) in cash and cash equivalents	1,826,527	(1,263,617)
Cash and cash equivalents at beginning of year	5,137,875	9,810,816
Cash and cash equivalents at end of period	6,964,402	8,547,199
Cash paid during the period for:
Interest	0	0
Taxes	$ 5,290,000	$ 80,000