Understanding the error caused by ng-pattern

I'm using ng-pattern in order to get the correct format of the user phone number. But when I tried to run the app Im getting an error stating Error: [$parse:lexerr] Lexer Error: Unexpected next character at columns 0-0 [^] in expression [^(?:\(\d{3}\)|\d{3}-)\d{3}-\d{4}$].I can't figure out what is the reason. Please I need help in this.

 <input type="tel" name="phoneno" maxlength=13  ng-model="phone.number" ng-pattern="^(?:\(\d{3}\)|\d{3}-)\d{3}-\d{4}$" required/>