Cash and Investments (Tables)

3 Months Ended

Mar. 31, 2021

Cash And Cash Equivalents [Abstract]

Short-term Investments

Short-term investments consisted of the following:

	March 31, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Short-term investments:
Bond funds	$	84	$	—	$	—	$	84
Total short-term investments	$	84	$	—	$	—	$	84

	December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Short-term investments:
Bond funds	$	84	$	—	$	—	$	84
Total short-term investments	$	84	$	—	$	—	$	84