Description of Business and Summary of Significant Accounting Policies (Computation of basic and diluted net income (loss) per share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule of computation of basic and diluted net income (loss) per share
Net income (loss)	$ (2,118)	[1]	$ (3,292)	[2]	$ (1,181)	[3]	$ 319	[4]	$ (2,814)	[5]	$ 6,027	[6]	$ 3,405	[7]	$ (278)	[2]	$ (6,272)	$ 6,340	$ 7,174
Weighted average common shares outstanding																	29,216	28,869	28,568
Effect of potentially dilutive securities
Weighted average common shares outstanding, assuming dilution																	29,216	28,903	28,709
Net income (loss) per share:
Basic (in dollars per share)																	$ (0.21)	$ 0.22	$ 0.25
Diluted (in dollars per share)																	$ (0.21)	$ 0.22	$ 0.25
Options to purchase common stock [Member]
Effect of potentially dilutive securities
Effect of potentially dilutive securities																	0	16	115
Restricted Stock Awards [Member]
Effect of potentially dilutive securities
Effect of potentially dilutive securities																	0	3	10
Restricted stock unit awards [Member]
Effect of potentially dilutive securities
Effect of potentially dilutive securities																	0	14	2
Employee Stock Purchase Plan [Member]
Effect of potentially dilutive securities
Effect of potentially dilutive securities																	0	1	14

[1] Includes a non-cash deferred tax expense of $1.6 million in connection with the probable repatriation of a portion of the unremitted earnings of a foreign subsidiary and a non-cash expense for stock-based compensation of $1.0 million.

[2] Includes a non-cash expense for stock-based compensation of $1.0 million.

[3] Includes a non-cash expense for stock-based compensation of $1.2 million.

[4] Includes a non-cash expense for stock-based compensation of $755,000.

[5] Includes a non-cash expense for stock-based compensation of $1.4 million.

[6] Includes a non-cash expense for stock-based compensation of $719,000.

[7] Includes a non-cash expense for stock-based compensation of $946,000