CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) (Common Shares [Member])	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Common Shares [Member]
Issuance of common shares related to stock plans	322,481	178,081	212,349
Issuance of common shares related to exercise of warrants		10,000,000
Issuance of common shares for cash offering	36,334,587	9,500,000	52,792,716