Segment Information - Condensed Balance Sheet Data for Segment (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 17,745,077	$ 10,559,899	$ 4,960,850	$ 22,152,802
Restricted cash and investments	212,625	216,702
Accounts receivable, net	12,627,063	11,386,584
Prepaid and other assets	4,164,320	2,787,909
Assets attributable to discontinued operations	3,500	8,500
Total current assets	34,752,585	24,959,594
Furniture, fixtures and equipment, net	850,866	853,377
Intangible assets, net	14,681,410	15,687,117
Deferred tax asset, non-current portion, net	18,638,737	21,316,520
Goodwill	54,824,648	54,824,648
Other assets	139,797	225,528
Total assets	123,888,043	117,866,784
Current liabilities:
Current portion of debt	0	0
Accrued expenses and other liabilities	4,170,687	3,578,227
Liability for option cancellations	0	268,341
Deferred revenue	22,885,287	20,284,178
Liabilities attributable to discontinued operations	299,025	342,138
Total current liabilities	27,354,999	24,472,884
Other long-term liabilities	419,638	522,941
Deferred tax liability, net	0	0
Total liabilities	27,774,637	24,995,825
Total stockholders' equity	96,113,406	92,870,959	74,556,620	77,510,331
Total liabilities and stockholders' equity	123,888,043	117,866,784
Reis Services [Member]
Current assets:
Cash and cash equivalents	17,562,000	10,347,000
Restricted cash and investments	213,000	217,000
Accounts receivable, net	12,627,000	11,386,000
Prepaid and other assets	213,000	187,000
Assets attributable to discontinued operations	0	0
Total current assets	30,615,000	22,137,000
Furniture, fixtures and equipment, net	836,000	829,000
Intangible assets, net	14,681,000	15,687,000
Deferred tax asset, non-current portion, net	285,000	285,000
Goodwill	57,203,000	57,203,000
Other assets	140,000	225,000
Total assets	103,760,000	96,366,000
Current liabilities:
Current portion of debt	0	0
Accrued expenses and other liabilities	3,157,000	2,623,000
Liability for option cancellations		0
Deferred revenue	22,885,000	20,284,000
Liabilities attributable to discontinued operations	0	0
Total current liabilities	26,042,000	22,907,000
Other long-term liabilities	420,000	523,000
Deferred tax liability, net	23,108,000	18,957,000
Total liabilities	49,570,000	42,387,000
Total stockholders' equity	54,190,000	53,979,000
Total liabilities and stockholders' equity	103,760,000	96,366,000
Other [Member]
Current assets:
Cash and cash equivalents	183,000	213,000
Restricted cash and investments	0	0
Accounts receivable, net	0	0
Prepaid and other assets	3,950,000	2,601,000
Assets attributable to discontinued operations	4,000	9,000
Total current assets	4,137,000	2,823,000
Furniture, fixtures and equipment, net	15,000	24,000
Intangible assets, net	0	0
Deferred tax asset, non-current portion, net	18,354,000	21,032,000
Goodwill	(2,378,000)	(2,378,000)
Other assets	0	0
Total assets	20,128,000	21,501,000
Current liabilities:
Current portion of debt	0	0
Accrued expenses and other liabilities	1,014,000	956,000
Liability for option cancellations		268,000
Deferred revenue	0	0
Liabilities attributable to discontinued operations	28,000	71,000
Total current liabilities	1,042,000	1,295,000
Other long-term liabilities	0	0
Deferred tax liability, net	(23,108,000)	(18,957,000)
Total liabilities	(22,066,000)	(17,662,000)
Total stockholders' equity	42,194,000	39,163,000
Total liabilities and stockholders' equity	20,128,000	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, non-current portion, 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
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