Marketable Securities

12 Months Ended

Dec. 31, 2018

Investments Debt And Equity Securities [Abstract]

Marketable Securities

4. Marketable Securities

All marketable securities were considered available-for-sale at December 31, 2018. The amortized cost, gross unrealized holding gains or losses, and fair value of the Company’s marketable securities by major security type at December 31, 2018 are summarized in the table below (in thousands):

	December 31, 2018
	Amortized Cost Basis		Unrealized Gains		Unrealized Losses			Fair Value
Marketable securities
U.S. treasuries	$	145,261	$	—	$	(15	)	$	145,246
Total	$	145,261	$	—	$	(15	)	$	145,246

The Company had no other-than-temporary impairments on its marketable securities during the year ended December 31, 2018. The Company has the intent and ability to hold all marketable securities until their maturities.

The Company held no marketable securities at December 31, 2017.