Cash, Cash Equivalents, and Short-Term Investments (Tables)

9 Months Ended

Sep. 30, 2012

Cash, Cash Equivalents, and Short-Term Investments [Abstract]

Summary of cash, cash equivalents and short-term investments

	As of September 30, 2012
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Cash and cash equivalents:
Cash	$	23,766	$	—	$	—	$	23,766
Bank deposits		12,519		—		—		12,519
Commercial paper		16,999		—		2		16,997
Money market funds		3,186		—		—		3,186
Total	$	56,470	$	—	$	2	$	56,468
Short-term investments:
Commercial paper	$	9,518	$	2	$	—	$	9,520
Corporate debt obligations		20,830		47		—		20,877
Bank deposits		10,063		—		—		10,063
US agency securities		2,003		—		1		2,002
Mutual funds		2,667		83		—		2,750
Total	$	45,081	$	132	$	1	$	45,212

	As of December 31, 2011
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Cash and cash equivalents:
Cash	$	26,023	$	—	$	—	$	26,023
Bank deposits		20,000		—		—		20,000
Money market funds		50,002		—		—		50,002
Total	$	96,025		—		—	$	96,025
Short-term investments - Mutual funds	$	1,644	$	—	$	57	$	1,587

Summary of cost and estimated fair value of short-term investments

	As of September 30, 2012
	Amortized Cost		Estimated Fair Value
Short-term investments:
Due within one year	$	38,772	$	38,934
Due within two years		6,254		6,278
Total	$	45,026	$	45,212