| Schedule of Financial Instruments, Measured at Fair Value on a Recurring and Non-recurring Basis |
As at December 31, 2018, the carrying amount and fair value of the Company’s financial instruments were as follows: | | | | | | | | | | | | | | | | | Level 1
$ | | Level 2
$ | | Level 3
$ | | Carrying Amount | Fair Value | | Carrying Amount | Fair Value | | Carrying Amount | Fair Value | Assets: | | | | | | | | | Cash equivalents: | | | | | | | | | Commercial paper | — |
| — |
| | 4,994 |
| 4,994 |
| | — |
| — |
| Repurchase agreements | — |
| — |
| | 60,000 |
| 60,005 |
| | — |
| — |
| Marketable securities: | | | | | | | | | U.S. term deposits | 127,500 |
| 128,241 |
| | — |
| — |
| | — |
| — |
| U.S. federal bonds | 230,898 |
| 231,299 |
| | — |
| — |
| | — |
| — |
| Canadian federal bonds | 19,967 |
| 19,962 |
| | — |
| — |
| | — |
| — |
| Corporate bonds and commercial paper | — |
| — |
| | 1,180,622 |
| 1,182,437 |
| | — |
| — |
| | | | | | | | | | Liabilities: | | | | | | | | | Derivative liabilities: | | | | | | | | | Foreign exchange forward contracts | — |
| — |
| | 12,216 |
| 12,216 |
| | — |
| — |
|
As at December 31, 2017, the carrying amount and fair value of the Company’s financial instruments were as follows: | | | | | | | | | | | | | | | | | Level 1
$ | | Level 2
$ | | Level 3
$ | | Carrying Amount | Fair Value | | Carrying Amount | Fair Value | | Carrying Amount | Fair Value | Assets: | | | | | | | | | Cash equivalents: | | | | | | | | | Corporate bonds and commercial paper | — |
| — |
| | 9,965 |
| 9,965 |
| | — |
| — |
| Marketable securities: | | | | | | | | | U.S. term deposits | 65,000 |
| 65,284 |
| | — |
| — |
| | — |
| — |
| U.S. federal bonds | 119,074 |
| 119,057 |
| | — |
| — |
| | — |
| — |
| Canadian federal bonds | 19,945 |
| 19,940 |
| | — |
| — |
| | — |
| — |
| Corporate bonds and commercial paper | — |
| — |
| | 592,343 |
| 593,554 |
| | — |
| — |
| Derivative assets: | | | | | | | | | Foreign exchange forward contracts | — |
| — |
| | 4,503 |
| 4,503 |
| | — |
| — |
| | | | | | | | | | Liabilities: | | | | | | | | | Derivative liabilities: | | | | | | | | | Foreign exchange forward contracts | — |
| — |
| | 795 |
| 795 |
| | — |
| — |
|
|