Investments (Tables)

6 Months Ended

Jul. 01, 2017

Amortized Cost and Fair Value of Available for Sale Investments

The amortized cost and fair values of available-for-sale investments are as follows at July 1, 2017 and December 31, 2016 (in thousands):

			Gross		Gross
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
July 1, 2017
Money market investments	$	14,422	$	—	$	—	$	14,422
Asset-backed securities		3,659		5		5		3,659
Corporate bonds and direct obligations of government agencies		80,122		311		158		80,275
U.S. Treasury obligations		11,988		—		8		11,980
Total	$	110,191	$	316	$	171	$	110,336
December 31, 2016
Money market investments	$	12,395	$	—	$	—	$	12,395
Asset-backed securities		4,027		3		19		4,011
Corporate bonds and direct obligations of government agencies		70,069		150		239		69,980
U.S. Treasury obligations		23,037		2		6		23,033
Total	$	109,528	$	155	$	264	$	109,419

Schedule of Unrealized Loss on Available for Sale Investments

For those available-for-sale investments with unrealized losses at July 1, 2017 and December 31, 2016, the following table summarizes the duration of the unrealized loss (in thousands):

	Less than 12 months				12 months or longer				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
July 1, 2017
Asset-backed securities	$	1,097	$	1	$	1,353	$	4	$	2,450	$	5
Corporate bonds and direct obligations of government agencies		29,252		125		2,276		33		31,528		158
U.S. Treasury obligations		11,980		8		—		—		11,980		8
Total	$	42,329	$	134	$	3,629	$	37	$	45,958	$	171
December 31, 2016
Asset-backed securities	$	1,363	$	6	$	2,314	$	13	$	3,677	$	19
Corporate bonds and direct obligations of government agencies		28,809		195		1,367		44		30,176		239
U.S. Treasury obligations		12,734		6		—		—		12,734		6
Total	$	42,906	$	207	$	3,681	$	57	$	46,587	$	264