Note 3 - Cash and Investments (Tables)

3 Months Ended

Mar. 31, 2023

Notes Tables

Cash, Cash Equivalents and Investments [Table Text Block]

	March 31, 2023		December 31, 2022
Cash	$	2,092	$	2,243
Cash equivalents (see detail in Note 4)		5,428		33,171
Restricted cash (see detail in Note 4)		221		221
Total cash, cash equivalents and restricted cash		7,741		35,635
Short-term investments		26,211		7
Total cash, cash equivalents, restricted cash and short-term investments	$	33,952	$	35,642

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	$	26,211	$	—	$	26,211	$	13	$	—	$	26,224
Total	$	26,211	$	—	$	26,211	$	13	$	—	$	26,224