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Note 13 - Supplemental Cash Flow Information (Details Textual) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2017	Mar. 28, 2017	Mar. 17, 2017	Dec. 31, 2016
Restricted Cash and Cash Equivalents, Current	$ 1,811	$ 11,927			$ 1,917
Interest-bearing Domestic Deposit, Certificates of Deposits		1,883
Certificates of Deposit [Member]
Restricted Cash and Cash Equivalents, Current					$ 1,917
6.25% Convertible Notes Due 2018 [Member]
Restricted Cash and Cash Equivalents, Current		$ 10,044
Debt Instrument, Interest Rate, Stated Percentage		6.25%	6.25%	6.25%	6.25%
Restatement Adjustment [Member] \| Accounting Standards Update 2016-18 [Member]
Proceeds from (Repayments of) Restricted Cash, Financing Activities	$ (13)