Segment Information - Condensed Balance Sheet Data for Segment (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 16,397,608	$ 10,559,899	$ 10,242,434	$ 4,960,850
Restricted cash and investments	212,492	216,702
Accounts receivable, net	6,966,014	11,386,584
Prepaid and other assets	3,127,905	2,787,909
Assets attributable to discontinued operations	3,500	8,500
Total current assets	26,707,519	24,959,594
Furniture, fixtures and equipment, net	808,835	853,377
Intangible assets, net	15,040,746	15,687,117
Deferred tax asset, net	19,937,520	21,316,520
Goodwill	54,824,648	54,824,648
Other assets	161,230	225,528
Total assets	117,480,498	117,866,784
Current liabilities:
Current portion of debt	0	0
Accrued expenses and other liabilities	3,780,047	3,578,227
Liability for option cancellations	172,809	268,341
Deferred revenue	18,187,918	20,284,178
Liabilities attributable to discontinued operations	289,063	342,138
Total current liabilities	22,429,837	24,472,884
Other long-term liabilities	464,358	522,941
Deferred tax liability, net	0	0
Total liabilities	22,894,195	24,995,825
Total stockholders' equity	94,586,303	92,870,959
Total liabilities and stockholders' equity	117,480,498	117,866,784
Reis Services [Member]
Current assets:
Cash and cash equivalents	16,235,000	10,347,000
Restricted cash and investments	212,000	217,000
Accounts receivable, net	6,966,000	11,386,000
Prepaid and other assets	302,000	187,000
Assets attributable to discontinued operations	0	0
Total current assets	23,715,000	22,137,000
Furniture, fixtures and equipment, net	791,000	829,000
Intangible assets, net	15,041,000	15,687,000
Deferred tax asset, net	285,000	285,000
Goodwill	57,203,000	57,203,000
Other assets	161,000	225,000
Total assets	97,196,000	96,366,000
Current liabilities:
Current portion of debt	0	0
Accrued expenses and other liabilities	2,715,000	2,623,000
Liability for option cancellations	0	0
Deferred revenue	18,188,000	20,284,000
Liabilities attributable to discontinued operations	0	0
Total current liabilities	20,903,000	22,907,000
Other long-term liabilities	464,000	523,000
Deferred tax liability, net	22,224,000	18,957,000
Total liabilities	43,591,000	42,387,000
Total stockholders' equity	53,605,000	53,979,000
Total liabilities and stockholders' equity	97,196,000	96,366,000
Other [Member]
Current assets:
Cash and cash equivalents	163,000	213,000
Restricted cash and investments	0	0
Accounts receivable, net	0	0
Prepaid and other assets	2,825,000	2,601,000
Assets attributable to discontinued operations	4,000	9,000
Total current assets	2,992,000	2,823,000
Furniture, fixtures and equipment, net	17,000	24,000
Intangible assets, net	0	0
Deferred tax asset, net	19,653,000	21,032,000
Goodwill	(2,378,000)	(2,378,000)
Other assets	0	0
Total assets	20,284,000	21,501,000
Current liabilities:
Current portion of debt	0	0
Accrued expenses and other liabilities	1,065,000	956,000
Liability for option cancellations	173,000	268,000
Deferred revenue	0	0
Liabilities attributable to discontinued operations	18,000	71,000
Total current liabilities	1,256,000	1,295,000
Other long-term liabilities	0	0
Deferred tax liability, net	(22,224,000)	(18,957,000)
Total liabilities	(20,968,000)	(17,662,000)
Total stockholders' equity	41,252,000	39,163,000
Total liabilities and stockholders' equity	20,284,000	21,501,000
Discontinued Operations [Member]
Current assets:
Cash and cash equivalents	0	0
Restricted cash and investments	0	0
Accounts receivable, net	0	0
Prepaid and other assets	0	0
Assets attributable to discontinued operations	0	0
Total current assets	0	0
Furniture, fixtures and equipment, net	0	0
Intangible assets, net	0	0
Deferred tax asset, net	0	0
Goodwill	0	0
Other assets	0	0
Total assets	0	0
Current liabilities:
Current portion of debt	0	0
Accrued expenses and other liabilities	0	0
Liability for option cancellations	0	0
Deferred revenue	0	0
Liabilities attributable to discontinued operations	271,000	271,000
Total current liabilities	271,000	271,000
Other long-term liabilities	0	0
Deferred tax liability, net	0	0
Total liabilities	271,000	271,000
Total stockholders' equity	(271,000)	(271,000)
Total liabilities and stockholders' equity	$ 0	$ 0