Cash and Investments (Tables)

3 Months Ended

Mar. 31, 2018

Investments Debt And Equity Securities [Abstract]

Cash, Cash Equivalents and Available-for-Sale Investments

The following tables present cash, cash equivalents, and available-for-sale investments as of the following dates (in thousands):

	March 31, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Market Value
Cash	$	56,232	$	—	$	—		$	56,232
Cash equivalents:
Money market funds		9,680		—		—			9,680
Marketable securities:
U.S. Government agency securities		1,500		—		(4	)		1,496
Certificate of deposits		6,999		—		(4	)		6,995
Commercial paper		5,481		—		(7	)		5,474
Corporate debt securities		37,017		—		(175	)		36,842
Asset-backed securities		7,204		—		(36	)		7,168
Total cash, cash equivalents, and marketable securities	$	124,113	$	—	$	(226	)	$	123,887
	December 30, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Market Value
Cash	$	34,643	$	—	$	—		$	34,643
Cash equivalents:
Money market funds		256		—		—			256
Marketable securities:
U.S. Government agency securities		1,500		—		(5	)		1,495
Certificates of deposits		14,498		—		(1	)		14,497
Commercial paper		7,952		—		(3	)		7,949
Corporate debt securities		48,073		—		(105	)		47,968
Asset-backed securities		10,240		—		(19	)		10,221
Total cash, cash equivalents, and marketable securities	$	117,162	$	—	$	(133	)	$	117,029