Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2013

Summary of Significant Accounting Policies

Schedule of non-controlling interest in subsidiary

(in thousands)	Non-Controlling Interest
Balance at December 31, 2011	$	574
Net loss attributable to Silver Creek	(118		)
Balance at March 31, 2012	$	456

	Non-Controlling Interest (Deficit)
Balance at December 31, 2012	$	97
Net loss attributable to Silver Creek	(170		)
Balance at March 31, 2013	$	(73	)

Schedule of available-for-sale securities, all of which have maturities of twelve months or less

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
March 31, 2013:
Certificate of deposit	$	240	$	—	$	—		$	240
Commercial paper	14,487		2		(6		)	14,483
Corporate debt securities	43,545		1		(17		)	43,529
Total	$	58,272	$	3	$	(23	)	$	58,252

Schedule of available-for-sale securities in an unrealized loss position

	Aggregate Fair Value		Unrealized Losses
	(in thousands)
March 31, 2013:
Commercial paper	$	9,487	$	(6	)
Corporate debt securities	35,505		(17		)
	$	44,992	$	(23	)