Share Capital Stock Options Outstanding (Details) (USD $)	12 Months Ended
Dec. 31, 2012
Number of Outstanding Options
Balance, December 31, 2011 (in shares)	12,864,002
Granted (in shares)	3,400,650
Exercised (in shares)	(482,841)
Forfeited (in shares)	(305,152)
Expired (in shares)	(76,997)
Balance, December 31, 2012 (in shares)	15,399,662
Number of Outstanding Options, Vested, or expected to vest, at December 31, 2012 through the life of the options	14,669,616
Weighted Average Exercise Price $/Option
Weighted Average Exercise Price $/Option, beginning balance (in dollars per share)	$ 4.90
Weighted Average Exercise Price $/Option, Granted (in dollars per share)	$ 5.78
Weighted Average Exercise Price $/Options Exercised (in dollars per share)	$ (2.97)
Weighted Average Exercise Price $/Options, Forfeited (in dollars per share)	$ (6.79)
Weighted Average Exercise Price $/Options, Expired (in dollars per share)	$ (6.82)
Weighted Average Exercise Price $/Option, ending balance (in dollars per share)	$ 5.11
Weighted Average Exercise Price $/Option, Vested, or expected to vest, at December 31, 2012 through the life of the options	$ 5.03

Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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Net number of share options (or share units) granted during the period.

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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Number of share options (or share units) exercised during the current period.

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