Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2013

Accounting Policies [Abstract]

Fair Value of the Company's Investments by Type

The following tables summarize the fair value of the Company’s investments by type. The estimated fair value of the Company’s fixed income investments are classified as Level 2 in the fair value hierarchy as defined in U.S. GAAP with the exception of U.S. Treasury securities, which are classified as Level 1. These valuations are based on observable direct and indirect inputs, primarily quoted prices of similar, but not identical, instruments in active markets or quoted prices for identical or similar instruments in markets that are not active. These fair values are obtained from independent pricing services which utilize Level 2 inputs.

	December 31, 2013
					Gross		Gross
	Amortized		Accrued		Unrealized		Unrealized		Estimated
	Cost		Interest		Gains		Losses		Fair Value
Obligations of U.S. Government and its agencies	$	4,899	$	1	$	1	$	—	$	4,901
Corporate debt securities		8,528		47		2		1		8,576
Commercial paper		5,994		—		2		—		5,996
Total investments	$	19,421	$	48	$	5	$	1	$	19,473

	December 31, 2012
					Gross		Gross
	Amortized		Accrued		Unrealized		Unrealized		Estimated
	Cost		Interest		Gains		Losses		Fair Value
U.S. Treasury securities	$	999	$	2	$	2	$	—	$	1,003
Obligations of U.S. Government and its agencies		3,505		6		2		—		3,513
Corporate debt securities		4,035		22		6		—		4,063
Commercial paper		1,695		—		1		—		1,696
Municipal obligations		5,541		27		16		—		5,584
Total investments	$	15,775	$	57	$	27	$	—	$	15,859

Scheduled Maturity for the Company's Investments

The following table summarizes the scheduled maturity for the Company’s investments at December 31, 2013 and 2012.

	2013		2012
Maturing in one year or less	$	16,891	$	14,708
Maturing after one year through two years		2,582		1,151
Maturing after two years		—		—
Total investments	$	19,473	$	15,859

Summary of Receivables

These receivables are evaluated to determine if any reserve or allowance should be established at each reporting date. At December 31, 2013 and 2012 the Company had the following receivables.

	December 31, 2013
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	90	$	1,573	$	1,663
Shionogi & Co. Ltd.		452		—		452
Total receivables	$	542	$	1,573	$	2,115
	December 31, 2012
	Billed		Unbilled		Total
U.S. Department of Health and Human Services	$	150	$	3,888	$	4,038
Shionogi & Co. Ltd.		524		—		524
Total receivables	$	674	$	3,888	$	4,562

Components of Inventories

The Company’s inventory consisted of the following:

	As of December 31,
	2013			2012
Supplies	$	263		$	263
Finished goods		3,980			3,980
Reserve for finished goods and supplies		(4,243	)		(4,243	)
Net inventories	$	—		$	—

Summary of Revenues

The Company recorded the following revenues for the years ended December 31:

	2013		2012		2011
Royalty revenue	$	2,562	$	3,317	$	—
Collaborative and other research and development revenues:
U.S. Department of Health and Human Services		13,585		14,026		17,099
Shionogi (Japan)		1,184		1,184		1,181
Mundipharma (United Kingdom)		—		7,766		1,277
Grants (United States)		—		—		86
Total collaborative and other research and development revenues		14,769		22,976		19,643
Total revenues	$	17,331	$	26,293	$	19,643

Schedule of Activity in the Restructuring Liability

The following table sets forth activity in the restructuring liability for the years ended December 31, 2013, 2012 and 2011.

	Employee separation costs			Facilities related charges			Total
Balance at December 31, 2010	$	158		$	—		$	158
Accruals		(158	)		—			(158	)
Balance at December 31, 2011		—			—			—
Accruals		1,662			97			1,759
Payments		(58	)		—			(58	)
Balance at December 31, 2012		1,604			97			1,701
Accruals		—			(97	)		(97	)
Payments		(1,604	)		—			(1,604	)
Balance at December 31, 2013	$	—		$	—		$	—