| 19. | Determination of fair values |
A number of the Company's accounting policies and disclosures require the determination of fair value, for both financial and non-financial assets and liabilities. Fair values have been determined for measurement and/or disclosure purposes based on the following models. When applicable, further information about the assumptions made in determining fair values is disclosed in the notes specific to that asset or liability.
| (a) | Intangible assets |
The fair value of intangible assets is based on the discounted cash flows expected to be derived from the use and eventual sale of the assets.
| (b) | Share-based payment transactions |
The fair value of the employee share options is measured using the Black-Scholes option pricing model. Measurement inputs include share price on measurement date, exercise price of the instrument, expected volatility (based on weighted average historical volatility adjusted for changes expected due to publicly available information), weighted average expected life of the instruments (based on historical experience and general option holder behaviour), expected dividends, and the risk-free interest rate (based on government bonds). Service and non-market performance conditions attached to the transactions are not taken into account in determining fair value.
| (c) | Royalty obligation |