Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net income	$ 2,829,124	$ 2,330,900
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization	414,744	172,554
Stock-based compensation expense	33,476	5,354
Deferred tax expense	(2,819,285)	(841)
Changes in operating assets and liabilities:
Accounts receivable	(1,239,234)	(717,785)
Income tax receivable	(12,000)	13,996
Prepaid expenses and other current assets	(83,320)	(44,143)
Patent costs	(5,414)	0
Accounts payable and accrued expenses	26,739	239,885
Deferred revenue	8,237,655	(12,345)
Net cash provided by operating activities	7,382,485	1,987,575
Cash flows from investing activities:
Maturity of marketable investments	12,233,583	5,197,986
Purchases of marketable investments	(15,169,104)	(7,343,620)
Net cash used in investing activities	(2,935,521)	(2,145,634)
Cash flows from financing activities:
Proceeds from stock option exercises	177,250	37,200
Payments for repurchase of common stock	(398,976)	(114,263)
Excess tax benefits from share-based payment arrangements	151,380	1,158,165
Net cash (used in) provided by financing activities	(70,346)	1,081,102
Increase in cash and cash equivalents	4,376,618	923,043
Cash and cash equivalents at beginning of year	5,137,875	9,810,816
Cash and cash equivalents at end of period	9,514,493	10,733,859
Cash paid during the period for:
Interest	0	0
Taxes	$ 4,080,000	$ 80,000