Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

Accounting Policies [Abstract]

Available-For-Sale Securities

Available-for-sale securities at December 31, 2015 consisted of the following:

	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(in thousands)
Corporate debt securities (Due within 1 year)	$	6,504	$	—	$	(3	)	$	6,501
Government agency securities (Due within 1 year)		1,000		—		—			1,000
	$	7,504	$	—	$	(3	)	$	7,501

Marketable Securities in Unrealized Loss Position

Marketable securities in an unrealized loss position at December 31, 2015 consisted of the following:

	Aggregate Fair Value		Unrealized Losses
		(in thousands)
Corporate debt securities (Due within 1 year)	$	4,100	$	(3	)
Government agency securities (Due within 1 year)		1,000		—
	$	5,100	$	(3	)

Summary of Cash Equivalents and Marketable Securities Measured at Fair Value on Recurring Basis

The following tables summarize the cash equivalents and marketable securities measured at fair value on a recurring basis in the accompanying consolidated balance sheets as of December 31, 2015 and 2014.

	Fair Value Measurements of Cash Equivalents and Marketable Securities as of December 31, 2015
	Level 1		Level 2		Level 3		Total
	(in thousands)
Cash equivalents	$	11,462	$	4,812	$	—	$	16,274
Marketable securities		—		7,501		—		7,501
	$	11,462	$	12,313	$	—	$	23,775

	Fair Value Measurements of Cash Equivalents as of December 31, 2014
	Level 1		Level 2		Level 3		Total
	(in thousands)
Cash equivalents	$	28,777	$	7,834	$	—	$	36,611

Stock-Based Compensation Expense

During the years ended December 31, 2015, 2014 and 2013, the Company recorded the following stock-based compensation expense:

	Years Ended December 31,
	2015		2014		2013
	(in thousands)
Research and development	$	298	$	899	$	1,991
General and administrative		765		1,909		1,949
Restructuring		69		—		—
Total stock-based compensation expense	$	1,132	$	2,808	$	3,940