Stock-Based Compensation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Stock-based compensation expense	$ 574	$ 532
Cost Of Sales [Member]
Stock-based compensation expense	7	6
Research and Development Expense [Member]
Stock-based compensation expense	153	120
Selling and Marketing Expense [Member]
Stock-based compensation expense	127	111
General and Administrative Expense [Member]
Stock-based compensation expense	$ 287	$ 295