Operations in Different Geographic Areas (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 28, 2012	Sep. 28, 2012	Jun. 29, 2012	Mar. 30, 2012	Dec. 30, 2011	Sep. 30, 2011	Jul. 01, 2011	Apr. 01, 2011	Dec. 28, 2012		Dec. 30, 2011		Dec. 31, 2010
Operations in Different Geographic Areas [Line Items]
Property, equipment and leasehold improvements, net	$ 27,446				$ 27,215				$ 27,446		$ 27,215
Revenues	72,946	73,298	74,484	71,925	67,916	65,951	65,106	73,473	292,653		272,446		248,753
UNITED STATES
Operations in Different Geographic Areas [Line Items]
Property, equipment and leasehold improvements, net	26,857				26,953				26,857		26,953
Revenues									260,760	[1]	239,994	[1]	220,527	[1]
Foreign Countries
Operations in Different Geographic Areas [Line Items]
Property, equipment and leasehold improvements, net	589				262				589		262
Revenues									$ 31,893	[1]	$ 32,452	[1]	$ 28,226	[1]

[1] Geographic revenues are allocated based on the location of the client.