Stockholders' Equity (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Summary of stock-based compensation recorded in expense categories
Total allocated share-based compensation expense	$ 1,860	$ 1,323
Cost of services and fulfillment [Member]
Summary of stock-based compensation recorded in expense categories
Total allocated share-based compensation expense	904	653
Selling and marketing [Member]
Summary of stock-based compensation recorded in expense categories
Total allocated share-based compensation expense	422	224
General and administrative [Member]
Summary of stock-based compensation recorded in expense categories
Total allocated share-based compensation expense	$ 534	$ 446