Investments (Tables)

3 Months Ended

Apr. 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 April 1, 2017 and December 31, 2016 (in thousands):

			Gross		Gross
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
April 1, 2017
Money market investments	$	18,410	$	—	$	—	$	18,410
Asset-backed securities		3,847		4		11		3,840
Corporate bonds and direct obligations of government agencies		74,950		191		183		74,958
U.S. Treasury obligations		12,747		—		11		12,736
Total	$	109,954	$	195	$	205	$	109,944
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 April 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
April 1, 2017
Asset-backed securities	$	1,268	$	2	$	2,240	$	9	$	3,508	$	11
Corporate bonds and direct obligations of government agencies		32,190		155		1,377		28		33,567		183
U.S. Treasury obligations		12,736		11		—		—		12,736		11
Total	$	46,194	$	168	$	3,617	$	37	$	49,811	$	205
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