Warrants
 3 Months Ended
Mar. 31, 2021
Equity [Abstract]  
Warrants Shareholders’ Equity
Under the Memorandum of Association and Articles of Association, or Articles, in effect as of March 31, 2021 and December 31, 2020, the Company had authorized an unlimited number of common shares with no par value.
As of March 31, 2021 and December 31, 2020, 24,094,051 and 23,925,789 common shares, respectively, were issued and 23,685,981 and 23,517,719 common shares, respectively, were outstanding.
During the three months ended March 31, 2021, the Company granted stock options to employees and contractors (see Note 10).
The Company had reserved common shares for future issuances as follows:
March 31,
2021		December 31,
2020
Warrants to purchase shares5,500 5,500 
Options to purchase shares2,161,165 2,012,960 
Remaining shares available under the 2018 Equity Incentive Plan2,079,873 1,641,112 
Shares issuable on vesting of restricted stock awards42,685 48,624 
Remaining shares available under the 2018 ESPP661,000 474,000 
Total4,950,223 4,182,196 
Warrants
In March 2017, the Company issued warrants for the purchase of 145,000 Class B ordinary shares to parties related to Rockport Ventures, with a fixed exercise price of $3.80 per share.
During the three months ended March 31, 2021, no warrants were exercised. As of each of March 31, 2021 and December 31, 2020, 5,500 warrants to purchase the Company’s common shares were outstanding and exercisable:
Warrant HolderIssue DateIn Connection WithWarrant to PurchaseSharesExercise PriceExpiration Date
Rockport3/3/2017Loan agreementCommon5,500$3.80 8/28/2022