Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2018	[1]	Jun. 30, 2017
Cash flows from operating activities:
Net income	$ 8,279,271		$ 5,968,844
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization	1,369,227		1,084,614
Stock-based compensation expense	96,314		66,952
Deferred tax expense	82,341		218,006
Extinguishment of accrued liabilities	(78,138)		0
Changes in operating assets and liabilities:
Accounts receivable	(684,061)		(852,490)
Income tax receivable	(666,874)		204,506
Prepaid expenses and other current assets	(213,476)		(176,202)
Patent costs	(79,485)		0
Accounts payable and accrued expenses	118,696		423,848
Deferred revenue	(139,680)		(637,459)
Net cash provided by operating activities	8,084,135		6,300,619
Cash flows from investing activities:
Maturity of marketable investments	37,279,000		32,855,741
Purchases of marketable investments	(40,596,520)		(37,669,248)
Net cash used in investing activities	(3,317,520)		(4,813,507)
Cash flows from financing activities:
Proceeds from stock option exercises	860,050		258,250
Payments for repurchase of common stock	0		(478,762)
Net cash provided by (used in) financing activities	860,050		(220,512)
Increase in cash and cash equivalents	5,626,665		1,266,600
Cash and cash equivalents at beginning of year	7,333,810		4,763,364
Cash and cash equivalents at end of period	12,960,475		6,029,964
Cash paid during the period for:
Interest	0		0
Taxes	$ 2,617,572		$ 2,770,000

[1] As of January 1, 2018, the Company adopted the requirements of ASC 606 using the modified retrospective adoption method, and as a result, there is a lack of comparability of certain amounts to the prior periods presented. See Note 2 for additional discussion.