Consolidated Balance Sheets (Parenthetical) (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Consolidated Balance Sheets [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 4,147	$ 3,002
Property and equipment, accumulated depreciation	12,341	10,289
Intangible assets, accumulated amortization	$ 293	$ 182
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	48,888,215	45,280,280
Common stock, shares outstanding	48,888,215	45,280,280