Note 3 - Cash and Investments (Tables)

9 Months Ended

Sep. 30, 2022

Notes Tables

Cash, Cash Equivalents and Investments [Table Text Block]

	September 30, 2022		December 31, 2021
Cash	$	2,063	$	2,506
Cash equivalents (see detail in Note 4)		24,102		37,023
Restricted cash (see detail in Note 4)		221		557
Total cash, cash equivalents and restricted cash		26,386		40,086
Short-term investments		10,677		—
Total cash, cash equivalents, restricted cash and short-term investments	$	37,063	$	40,086

Debt Securities, Held-to-Maturity [Table Text Block]

							Gross		Gross
	Amortized		Allowance for		Net carrying		unrealized		unrealized		Fair
	cost		credit losses		amount		gains		losses		value
U.S. treasury securities	$	10,677	$	—	$	10,677	$	—	$	3	$	10,674
Total	$	10,677	$	—	$	10,677	$	—	$	3	$	10,674