Investments (Tables)

12 Months Ended

Dec. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Summary of Short-Term Investments

The following tables summarize our short-term investments (in thousands):

	Maturity (in years)	Amortized cost		Unrealized					Estimated fair value
				Gains		Losses
As of December 31, 2016
Corporate debt securities	2 or less	$	49,185	$	12	$	(77	)	$	49,120
Certificates of deposit	1 or less	9,291		—		—			9,291
Commercial paper	1 or less	1,247		—		—			1,247
U.S. treasury securities	1 or less	1,001		—		(1		)	1,000
Debt securities of U.S. government-sponsored agencies	1 or less	512		—		—			512
Total		$	61,236	$	12	$	(78	)	$	61,170

	Maturity (in years)	Amortized cost		Unrealized					Estimated fair value
				Gains		Losses
As of December 31, 2015
Corporate debt securities	2 or less	$	81,054	$	16	$	(103	)	$	80,967
Certificates of deposit	2 or less	13,640		—		—			13,640
Commercial paper	1 or less	3,490		6		—			3,496
Total		$	98,184	$	22	$	(103	)	$	98,103