Share-Based Compensation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Share-based compensation expense
Allocated share-based compensation expense	$ 1,949	$ 1,694	$ 3,671	$ 3,313
Less income tax effect	(682)	(552)	(1,231)	(1,102)
Net share-based compensation expense	1,267	1,142	2,440	2,211
Cost of revenues [Member]
Share-based compensation expense
Allocated share-based compensation expense	243	270	477	514
Research and development [Member]
Share-based compensation expense
Allocated share-based compensation expense	833	652	1,523	1,304
Selling, general and administrative [Member]
Share-based compensation expense
Allocated share-based compensation expense	$ 873	$ 772	$ 1,671	$ 1,495