Income Taxes - Other Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Taxes [Line Items]
Tax benefit from the exercises of non-qualified stock options and vesting of restricted stock under our stock-based incentive plans		$ 900,000	$ 100,000
Provision for undistributed earnings of our foreign subsidiaries	0
State Administration of Taxation, China [Member]
Income Taxes [Line Items]
Period of recognition for deductible expenses or deferred tax assets	5 years
Increase in income tax expense due to write-off of deferred tax assets for social insurance and housing funds	$ 700,000	$ 200,000	$ 600,000