Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2017

Fair Value Measurements

Schedule of financial instruments measured at fair value on recurring basis

	Actively Quoted		Significant
	Markets for		Other		Significant
	Identical		Observable		Unobservable		Balance at
	Assets		Inputs		Inputs		September 30,
	Level 1		Level 2		Level 3		2017
	(In thousands)
As of September 30, 2017:
Assets
Money market deposits	$	9,677	$	—	$	—	$	9,677
Commercial paper		—		39,632		—		39,632
Corporate debt securities		—		36,310		—		36,310
Total	$	9,677	$	75,942	$	—	$	85,619

	Actively Quoted		Significant
	Markets for		Other		Significant
	Identical		Observable		Unobservable		Balance at
	Assets		Inputs		Inputs		December 31,
	Level 1		Level 2		Level 3		2016
	(In thousands)
As of December 31, 2016:
Assets
Money market deposits	$	13,198	$	—	$	—	$	13,198
Commercial paper		—		32,421		—		32,421
Corporate debt securities		—		14,869		—		14,869
Corporate equity securities		—		9,295		—		9,295
Total	$	13,198	$	56,585	$	—	$	69,783

Summary of available-for-sale marketable securities

	September 30, 2017
	Cost or		Gross		Gross		Total
	Amortized		Unrealized		Unrealized		Estimated
	Cost		Gains		Losses		Fair Value
	(In thousands)
Commercial paper	$	39,637	$	4	$	(9)	$	39,632
Corporate debt securities		36,333		—		(23)		36,310
Total	$	75,970	$	4	$	(32)	$	75,942

	December 31, 2016
	Cost or		Gross		Gross		Total
	Amortized		Unrealized		Unrealized		Estimated
	Cost		Gains		Losses		Fair Value
	(In thousands)
Commercial paper	$	32,350	$	71	$	—	$	32,421
Corporate debt securities		14,868		3		(2)		14,869
Corporate equity securities		7,348		1,947		—		9,295
Total	$	54,566	$	2,021	$	(2)	$	56,585