Note 9 - Net Loss Per Share of Common Stock (Details Textual) - shares shares in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Weighted Average Number of Shares Outstanding, Diluted, Adjustment, Total (in shares)	0	0

The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=124432515&loc=d3e3550-109257

Name:	us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration