Consolidated Balance Sheets (Parentheticals) (USD $) In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Allowance for doubtful accounts and customer credits	$ 6.5	$ 5.3
Stockholders' equity:
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	142,694,732	140,945,171
Common stock, shares outstanding	142,694,732	140,945,171