Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Accounts receivable, net of allowances of $1,270 and $1,170	$ 1,270	$ 1,170
Property and equipment, net of accumulated depreciation of $39,297 and $36,344	39,297	36,344
Intangible assets, net of accumulated amortization of $24,030 and $22,292	$ 24,030	$ 22,292
Common stock, par value (usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (shares)	290,000,000	290,000,000
Common stock, shares issued (shares)	84,134,000	82,820,000
Common stock, shares outstanding (shares)	77,709,000	76,395,000