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

3 Months Ended

Mar. 31, 2017

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 March 31, 2017
			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
Cash and cash equivalents:
Cash	$	65,293	$	—	$	—	$	65,293
Commercial paper		4,996		—		2		4,994
Money market funds		66,031		—		—		66,031
Total	$	136,320	$	—	$	2	$	136,318
Short-term investments:
Commercial paper	$	20,175	$	—	$	8	$	20,167
Corporate debt obligations		137,200		1		310		136,891
US government agencies		18,998		—		42		18,956
Bank deposits		480		—		—		480
Total	$	176,853	$	1	$	360	$	176,494

	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

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

The following table summarizes the cost and estimated fair value of short-term investments based on stated effective maturities as of March 31, 2017 (in thousands):

	As of March 31, 2017
			Estimated
	Amortized		Fair
	Cost		Value
Short-term investments:
Due within one year	$	89,856	$	89,696
Due within two years		86,997		86,798
Total	$	176,853	$	176,494

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 March 31, 2017
	Less than 12 Months				12 Months or Greater				Total
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Commercial paper	$	14,215	$	8	$	—	$	—	$	14,215	$	8
Corporate debt obligations		108,446		271		25,948		38		134,394	$	309
US government agencies		11,459		38		7,496		4		18,955		42
Bank deposits		240		1		-		-		240	$	1
	$	134,360	$	318	$	33,444	$	42	$	167,804	$	360

	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