Available-for-Sale Securities (Tables)

6 Months Ended

Jun. 30, 2017

Table Text Blocks

Schedule of summary of available-for-sale securities

The following tables summarize the available-for-sale securities held at June 30,  2017 and December 31, 2016 (in thousands):

			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
June 30, 2017
U.S. Treasury securities	$	20,495	$	—	$	(5)	$	20,490
U.S. government-sponsored securities		70,292		—		(19)		70,273
Total	$	90,787	$	—	$	(24)	$	90,763

			Gross		Gross
	Amortized		Unrealized		Unrealized		Fair
	Cost		Gains		Losses		Value
December 31, 2016
U.S. Treasury securities	$	115,026	$	6	$	(11)	$	115,021
U.S. government-sponsored securities		136,193		10		(12)		136,191
Total	$	251,219	$	16	$	(23)	$	251,212