Summary of Business and Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2012

Summary of Business and Significant Accounting Policies [Abstract]

Property and equipment estimated useful lives


Computer equipment and software		3-5 years
Furniture and fixtures		3-5 years
Leasehold improvements		Shorter of the lease term or estimated useful life

Fair value of stock option grant and stock purchase right granted under ESPP estimated on date of grant using Black-Scholes option pricing model

The following is a summary of short-term investments at June 30, 2012 (in thousands):


		June 30, 2012
		Amortized Cost				Gross Unrealized Gains				Gross Unrealized Losses				Estimated Fair Value
Available-for-sale securities:
Commercial paper		$	5,993			$	4			$	(1	)		$	5,996
Corporate notes and bonds			14,781				3				(8	)			14,776
U.S. government agency securities			2,023				—				—				2,023

Total available-for-sale securities		$	22,797			$	7			$	(9	)		$	22,795