Investments (Tables)

9 Months Ended

Sep. 30, 2021

Investments [Abstract]

Schedule of investments in fixed maturity securities

Investment type	Amortized Cost		Unrealized (Losses) Gains			Fair Value
Corporate bonds(1)	$	31,577	$	(8	)	$	31,569
Commercial paper		5,299		1			5,300
Total	$	36,876	$	(7	)	$	36,869

​(1)     Classified as available-for-sale with original maturities of ninety-one to 365 days on the Balance Sheets as of September 30, 2021.