Cash, Cash Equivalents and Investments (Tables)

6 Months Ended

Jun. 30, 2012

Cash, Cash Equivalents and Investments

Schedule of cash, cash equivalents, and investments

	June 30, 2012
	Cost		Gross Unrealized  Losses			Gross Unrealized Gains		Fair Value
Cash and Cash Equivalents:
Cash on hand	$	107,595	$	—		$	—	$	107,595
Available-for-sale securities:
Money market funds	49,917		—			—		49,917
U.S. Treasury bills	16,241		—			—		16,241
Total available-for-sale securities	66,158		—			—		66,158
Total cash and cash equivalents	$	173,753	$	—		$	—	$	173,753
Short-term Investments:
Available-for-sale securities:
Corporate bonds	$	62,993	$	(36	)	$	197	$	63,154
Municipal bonds	32,495		(8		)	45		32,532
U.S. government bonds	12,647		—			8		12,655
Asset-backed securities	10,655		—			10		10,665
Variable-rate demand notes	8,980		—			1		8,981
U.S. Treasury bills	7,149		—			1		7,150
International government bonds	2,111		(1		)	—		2,110
U.S. government agency	900		—			—		900
Total short-term investments	$	137,930	$	(45	)	$	262	$	138,147
Long-term Investments:
Available-for-sale securities:
Auction rate securities	$	12,525	$	(1,497	)	$	—	$	11,028
Total long-term investments	$	12,525	$	(1,497	)	$	—	$	11,028

	December 31, 2011
	Cost		Gross Unrealized Losses			Gross Unrealized Gains		Fair Value
Cash and Cash Equivalents:
Cash on hand	$	44,113	$	—		$	—	$	44,113
Available-for-sale securities:
Money market funds	50,851		—			—		50,851
Total cash and cash equivalents	$	94,964	$	—		$	—	$	94,964
Short-term Investments:
Available-for-sale securities:
Corporate bonds	$	75,189	$	(363	)	$	234	$	75,060
Municipal bonds	56,915		(12		)	81		56,984
Variable-rate demand notes	41,280		—			—		41,280
U.S. government agency	19,820		(12		)	28		19,836
U.S. Treasury bills	8,600		—			—		8,600
Asset-backed securities	5,743		(5		)	1		5,739
U.S. government bonds	2,507		—			—		2,507
Certificates of deposit	1,570		—			—		1,570
International government bonds	950		—			—		950
Total short-term investments	$	212,574	$	(392	)	$	344	$	212,526
Long-term Investments:
Available-for-sale securities:
Auction rate securities	$	19,225	$	(1,748	)	$	—	$	17,477
Total long-term investments	$	19,225	$	(1,748	)	$	—	$	17,477

Schedule of available-for-sale investments in continuous unrealized loss position by length of time

	Less Than 12 Months					12 Months or Greater					Total
As of June 30, 2012	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate bonds	$	13,019	$	(36	)	$	—	$	—		$	13,019	$	(36	)
Auction rate securities	—		—			11,028		(1,497		)	11,028		(1,497		)
Municipal bonds	8,431		(8		)	—		—			8,431		(8		)
International government bonds	2,110		(1		)	—		—			2,110		(1		)
	$	23,560	$	(45	)	$	11,028	$	(1,497	)	$	34,588	$	(1,542	)

	Less Than 12 Months					12 Months or Greater					Total
As of December 31, 2011	Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses			Fair Value		Gross Unrealized Losses
Corporate bonds	$	25,438	$	(363	)	$	—	$	—		$	25,438	$	(363	)
Auction rate securities	—		—			17,477		(1,748		)	17,477		(1,748		)
Municipal bonds	10,437		(12		)	—		—			10,437		(12		)
U.S. government agency	5,772		(12		)	—		—			5,772		(12		)
Asset-backed securities	4,539		(5		)	—		—			4,539		(5		)
	$	46,186	$	(392	)	$	17,477	$	(1,748	)	$	63,663	$	(2,140	)

Summarization of contractual underlying maturities of available-for-sale investments

	Cost		Fair Value
Due in one year or less	$	109,030	$	109,112
Due after one year through ten years	87,528		87,663
Due after ten years	20,055		18,558
	$	216,613	$	215,333