Fair Value of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2015

Fair Value of Financial Instruments

Schedule of fair value of financial assets and liabilities measured at fair value and classification by level of input

	Fair Value Measurements as of
	March 31, 2015
(in thousands)	Level 1		Level 2		Level 3		Total
Investments:
Money market funds	$	10,476	$	—	$	—	$	10,476
Federal agency securities		—		11,506		—		11,506
Commercial paper		—		—		—		—
Corporate debt securities		—		6,091		—		6,091
Total assets measured at fair value	$	10,476	$	17,597	$	—	$	28,073
Financing derivative		—		—		92		92
Total liabilities measured at fair value	$	—	$	—	$	92	$	92

	Fair Value Measurements as of
	December 31, 2014
(in thousands)	Level 1		Level 2		Level 3		Total
Investments:
Money market funds	$	9,663	$	—	$	—	$	9,663
Federal agency securities		—		13,770		—		13,770
Commercial paper		—		1,500		—		1,500
Corporate debt securities		—		14,520		—		14,520
Total assets measured at fair value	$	9,663	$	29,790	$	—	$	39,453
Financing derivative		—		—		89		89
Total liabilities measured at fair value	$	—	$	—	$	89	$	89

Schedule of changes in financial instruments measured at fair value using Level 3 inputs

	Fair Value Measurements of
	Level 3 Liabilities
	(in thousands)
Balance at December 31, 2014	$	89
(Gain) loss on remeasurement of the financing derivative liability		3
Balance at March 31, 2015	$	92