Tax Loss and Credit Carryforwards (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
U.S. federal
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	$ 7,706		$ 34,297
Tax credit carryforwards, Expiration year	Dec. 31, 2027
State and Local
Tax Credit Carryforward [Line Items]
Tax loss carryforwards	9,856		36,201
Tax credit carryforwards, Expiration year	Dec. 31, 2027
Contributions Carryforwards
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	166		85
Tax credit carryforwards, Expiration year	Dec. 31, 2015
Illinois Edge
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	2,938	[1]	1,654	[1]
Tax credit carryforwards, Expiration year	Dec. 31, 2017	[1]
New York Unincorporated Business
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	875	[1]
Tax credit carryforwards, Expiration year	Dec. 31, 2021	[1]
Research and Development
Tax Credit Carryforward [Line Items]
Tax credit carryforwards			53
Tax credit carryforwards, Expiration year	Dec. 31, 2031
Alternate Minimum Tax
Tax Credit Carryforward [Line Items]
Tax credit carryforwards			$ 240
Tax credit carryover, Expiration year	No expiration

[1] Amounts are before the federal benefit of state tax