Segment Information - Condensed Balance Sheet Data for Segments (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 28,657,956	$ 17,745,077	$ 10,559,899	$ 4,960,850
Restricted cash and investments	212,268	212,625
Accounts receivable, net	13,741,169	12,627,063
Prepaid and other assets	670,339	369,820
Total current assets	43,281,732	30,954,585
Furniture, fixtures and equipment, net	804,427	850,866
Intangible assets, net	15,686,954	14,681,410
Deferred tax asset, net	18,429,737	22,436,737
Goodwill	54,824,648	54,824,648
Other assets	171,728	139,797
Total assets	133,199,226	123,888,043
Current liabilities:
Current portion of debt	0	0
Accrued expenses and other liabilities	5,898,226	4,170,687
Deferred revenue	25,291,499	22,885,287
Liabilities attributable to discontinued operations	145,737	299,025
Total current liabilities	31,335,462	27,354,999
Other long-term liabilities	284,316	419,638
Deferred tax liability, net	0	0
Total liabilities	31,619,778	27,774,637
Total stockholders' equity	101,579,448	96,113,406	$ 92,870,959	$ 74,556,620
Total liabilities and stockholders' equity	133,199,226	123,888,043
Reis Services [Member]
Current assets:
Cash and cash equivalents	28,465,000	17,562,000
Restricted cash and investments	212,000	213,000
Accounts receivable, net	13,741,000	12,627,000
Prepaid and other assets	417,000	213,000
Total current assets	42,835,000	30,615,000
Furniture, fixtures and equipment, net	798,000	836,000
Intangible assets, net	15,687,000	14,681,000
Deferred tax asset, net	285,000	285,000
Goodwill	57,203,000	57,203,000
Other assets	172,000	140,000
Total assets	116,980,000	103,760,000
Current liabilities:
Current portion of debt	0	0
Accrued expenses and other liabilities	4,502,000	3,157,000
Deferred revenue	25,291,000	22,885,000
Liabilities attributable to discontinued operations	0	0
Total current liabilities	29,793,000	26,042,000
Other long-term liabilities	284,000	420,000
Deferred tax liability, net	29,498,000	23,108,000
Total liabilities	59,575,000	49,570,000
Total stockholders' equity	57,405,000	54,190,000
Total liabilities and stockholders' equity	116,980,000	103,760,000
Other [Member]
Current assets:
Cash and cash equivalents	193,000	183,000
Restricted cash and investments	0	0
Accounts receivable, net	0	0
Prepaid and other assets	193,000	156,000
Total current assets	386,000	339,000
Furniture, fixtures and equipment, net	6,000	15,000
Intangible assets, net	0	0
Deferred tax asset, net	18,145,000	22,152,000
Goodwill	(2,378,000)	(2,378,000)
Other assets	0	0
Total assets	16,159,000	20,128,000
Current liabilities:
Current portion of debt	0	0
Accrued expenses and other liabilities	1,397,000	1,014,000
Deferred revenue	0	0
Liabilities attributable to discontinued operations	26,000	28,000
Total current liabilities	1,423,000	1,042,000
Other long-term liabilities	0	0
Deferred tax liability, net	(29,498,000)	(23,108,000)
Total liabilities	(28,075,000)	(22,066,000)
Total stockholders' equity	44,234,000	42,194,000
Total liabilities and stockholders' equity	16,159,000	20,128,000
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	60,000	0
Total current assets	60,000	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	60,000	0
Current liabilities:
Current portion of debt	0	0
Accrued expenses and other liabilities	0	0
Deferred revenue	0	0
Liabilities attributable to discontinued operations	120,000	271,000
Total current liabilities	120,000	271,000
Other long-term liabilities	0	0
Deferred tax liability, net	0	0
Total liabilities	120,000	271,000
Total stockholders' equity	(60,000)	(271,000)
Total liabilities and stockholders' equity	$ 60,000	$ 0