Note 13 - Fair Value Measurements and Disclosures (Details) (USD $)	Jun. 30, 2014 Fair Value, Inputs, Level 1 [Member] Convertible Notes 2017 [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 1 [Member] Convertible Notes 2017 [Member]	Jun. 30, 2014 Fair Value, Inputs, Level 1 [Member] Convertible Notes 2015 [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 1 [Member] Convertible Notes 2015 [Member]	Sep. 30, 2013 $40 Million Secured Debt Facility [Member]	May 31, 2013 $40 Million Secured Debt Facility [Member]	Jan. 31, 2011 $40 Million Secured Debt Facility [Member]	May 31, 2013 $75 Million Secured Debt Facility [Member]	Jul. 31, 2011 $75 Million Secured Debt Facility [Member]	Jun. 30, 2014 Convertible Notes 2017 [Member]		Dec. 31, 2013 Convertible Notes 2017 [Member]		Sep. 30, 2013 Convertible Notes 2017 [Member]	Jun. 30, 2014 Convertible Notes 2015 [Member]		Dec. 31, 2013 Convertible Notes 2015 [Member]		Mar. 31, 2010 Convertible Notes 2015 [Member]
Note 13 - Fair Value Measurements and Disclosures (Details) [Line Items]
Debt Instrument, Face Amount					$ 40,000,000	$ 25,500,000	$ 40,000,000	$ 75,000,000	$ 75,000,000
Convertible Debt, Fair Value Disclosures	$ 202,100,000	$ 130,100,000	$ 60,700,000	$ 79,700,000						$ 202,076,000	[1]	$ 130,094,000	[1]	$ 124,500,000	$ 60,684,000	[2]	$ 79,663,000	[2]	$ 136,300,000

[1] The Company estimated the fair value of the 2017 Convertible Notes to be approximately $202.1 million and $130.1 million at June 30, 2014 and December 31, 2013, respectively, based on observed market prices for the same or similar types of debt issues. The fair value of the 2017 Convertible Notes is considered to be a Level 1 measurement on the fair value hierarchy.

[2] The Company estimated the fair value of the 2015 Convertible Notes to be approximately $60.7 million and $79.7 million at June 30, 2014 and December 31, 2013, respectively, based on observed market prices for the same or similar types of debt issues. The fair value of the 2015 Convertible Notes is considered to be a Level 1 measurement on the fair value hierarchy.