Note 4 - Cash, Cash Equivalents and Restricted Cash (Tables)

9 Months Ended

Sep. 30, 2020

Notes Tables

Schedule of Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Table Text Block]

(in thousands)	September 30, 2020		December 31, 2019
Cash	$	10,691	$	12,041
Cash equivalents:
U.S. Government money market funds		12,408		14,971
Tri-party reverse repurchase agreements (collateralized by at least 102% U.S. Treasury and Agency Securities)		137,522		154,258
Restricted cash, non-current		100		100
Total cash, cash equivalents and restricted cash	$	160,721	$	181,370