Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts receivable, allowance	$ 2,474	$ 1,937
Accumulated amortization	$ 28,575	$ 14,137
Common Stock, par value
Common Stock, shares authorized	55,000,000	55,000,000
Common Stock, shares issued	29,818,225	23,515,571
Common Stock, shares outstanding	29,818,225	23,515,571