Cash, Cash Equivalents, and Short-Term Investments (Tables)

12 Months Ended

Dec. 31, 2016

Cash And Cash Equivalents [Abstract]

Summary of Cash, Cash Equivalents and Short-Term Investments

Cash, cash equivalents and short-term investments consist of the following (in thousands):

	As of December 31, 2016
			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
Cash and cash equivalents:
Cash	$	63,642	$	—	$	—	$	63,642
Commercial paper		6,995		—		2		6,993
Money market funds		36,708		—		—		36,708
Total	$	107,345	$	—	$	2	$	107,343
Short-term investments:
Commercial paper	$	14,245	$	—	$	8	$	14,237
Corporate debt obligations		110,062		—		347		109,715
US government agencies		18,998		2		50		18,950
Bank deposits		10,846		1		—		10,847
Total	$	154,151	$	3	$	405	$	153,749

	As of December 31, 2015
			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
Cash and cash equivalents:
Cash	$	57,906	$	—	$	—	$	57,906
Bank deposits		10,253		—		—		10,253
Commercial paper		13,896		—		3		13,893
Money market funds		86,200		—		—		86,200
Total	$	168,255	$	—	$	3	$	168,252
Short-term investments:
Corporate debt obligations	$	86,590	$	2	$	300		86,292
Bank deposits		10,263		—		—		10,263
Total	$	96,853	$	2	$	300	$	96,555

Summary of Cost and Estimated Fair Value of Short-Term Investments

The following table sets forth the cost and estimated fair value of short-term investments based on stated effective maturities as of December 31, 2016 (in thousands):

	As of December 31, 2016
			Estimated
	Amortized		Fair
	Cost		Value
Short-term investments:
Due in 2017	$	84,406	$	84,315
Due in 2018		69,745		69,434
Total	$	154,151	$	153,749

Schedule of Short-Term Investments at Fair Value and Length of Continuous Unrealized Loss Position

The following tables show the short-term investments in an unrealized loss position and the related gross unrealized losses and fair value and length of time that the short-term investments have been in a continuous unrealized loss position (in thousands):

	As of December 31, 2016
	Less than 12 Months				12 Months or Greater				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Commercial paper	$	14,237	$	8					$	14,237	$	8
Corporate debt obligations		78,821		323		29,689		24		108,510		347
US government agencies		11,451		46		3,496		4		14,947		50
	$	104,509	$	377	$	33,185	$	28	$	137,694	$	405

	As of December 31, 2015
	Less than 12 Months				12 Months or Greater				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Corporate debt obligations	$	73,673	$	286	$	10,609	$	14	$	84,282	$	300
	$	73,673	$	286	$	10,609	$	14	$	84,282	$	300