Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2018

All marketable securities were classified as held-to-maturity as of the dates presented and the carrying amounts of held-to-maturity securities were as follows:

(in thousands)	September 30, 2018		December 31, 2017		September 30, 2017
U.S. Government and agency obligations	$	30,000	$	17,910	$	12,909
Commercial paper		—		49,865		34,905
Corporate bonds		5,010		—		—
Total short-term marketable securities		35,010		67,775		47,814
U.S. Government and agency obligations		46,093		59,993		69,991
Corporate bonds		—		5,022		—
Total long-term marketable securities		46,093		65,015		69,991
Total marketable securities	$	81,103	$	132,790	$	117,805

Scheduled maturities of held-to-maturity investments were as follows:

(in thousands)	September 30, 2018
Due within one year	$	35,010
Due in one to five years		46,093
Total	$	81,103