Note 3 - Strategic Partnership Agreement With Advantest and Related Party Transactions (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		9 Months Ended
	Jul. 29, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Common Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.00015		$ 0.00015		$ 0.00015
Proceeds from Issuance of Common Stock				$ 64,995	$ 0
Revenue from Contract with Customer, Including Assessed Tax		$ 23,112	$ 21,914	65,678	$ 63,023
Strategic Partnership for Joint Development and Sales Technology Solutions [Member]
Stock Issued During Period, Shares, New Issues (in shares)	3,306,924
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.00015
Shares Issued, Price Per Share (in dollars per share)	$ 19.7085
Proceeds from Issuance of Common Stock	$ 65,200
Stock Issuance, Lock-up Period (Year)	5 years
Stock Issuance, Standstill Period (Year)	5 years
Software Platform Subscription, Term (Year)	5 years
Amendment #1 to Software License & Related Services Agreement [Member]
Software License Agreement, Aggregate Subscription Price		50,000		50,000
Revenue from Contract with Customer, Including Assessed Tax		1,000		1,000
Related Party Transaction, Due from (to) Related Party, Total		9,000		9,000
Contract with Customer, Liability, Total		8,000		8,000
Commercial Agreement With Advantest [Member]
Costs and Expenses, Related Party		$ 0		$ 0