Note 4 - Stock-based Compensation (Tables)

3 Months Ended

Jun. 30, 2022

Notes Tables

Share-Based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

	Three Months Ended June 30,
	2022		2021
Cost of revenues	$	29	$	91
Research and development		179		247
Selling, general and administrative		825		954
Total	$	1,033	$	1,292

Disclosure of Share-Based Compensation Arrangements by Share-Based Payment Award [Table Text Block]

	Three Months Ended June 30,
	2022	2021
Expected volatility	71.4%	N/A
Risk-free interest rate	3.1%	N/A
Expected life (years)	6.14	N/A
Dividend yield	None	N/A