Using exception ctaching as a validation method...?

Hi everyone.
I'm trying to write a program that calculates commissions. When my program asks for the total sales of the salesperson, I have code that validates the number is above 0. I want to catch the InputMismatchException for when people attempt to type alphabet/special characters. In the catch block I display an error message and set total sales to -1. Since the try/catch blocks are nested within a do-while loop, I thought this would circle back to ask for input. Instead the program just repeatedly displays the error message and I have to exit the cmd to get it to stop.
Why is this happening and how can I fix it?
Here's my code

public class Salesperson
{
	private int fixedSalary;
	private double totalSales;
	private double percentCommission;

	public Salesperson(int salary, double sales, double commission)
	{
		setFixedSalary( salary );
		setTotalSales( sales );
		setPercentCommission( commission );
	}
	
	public void setFixedSalary( int salary )
	{
		fixedSalary = salary;
	}

	public int getFixedSalary()
	{
		return fixedSalary;
	}

	public void setTotalSales( double sales )
	{
		totalSales = sales;
	}

	public double getTotalSales()
	{
		return totalSales;
	}

	public void setPercentCommission( double commission )
	{
		percentCommission = commission;
	}

	public double getPercentCommission()
	{
		return percentCommission;
	}

	public double totalCommission()
	{
		double totalCommission = totalSales * percentCommission;
		return totalCommission;
	}
}

import java.util.Scanner;
import java.util.InputMismatchException;

public class Compensation
{
	public static void main( String args[])
	{
		Salesperson aSalesperson = new Salesperson(40_000, 0, .05);
		Scanner input = new Scanner(System.in);
		
		System.out.println("Welcome to the Annual Compensation Calculator!");
		
		do
		{
			try
			{
				System.out.println("How much did you earn in total sales this year?");
				aSalesperson.setTotalSales( input.nextDouble() );
			
				if (aSalesperson.getTotalSales() <= 0)
					System.out.println("Input Error.  Please enter a positive number.");
			}
			catch (InputMismatchException e)
			{
				System.out.println("Please type your answer using number keys with no special characters.");
				aSalesperson.setTotalSales( -1 );					
			}
			
		} while (aSalesperson.getTotalSales() <= 0); 
		
		System.out.println();

		System.out.println("You have a base salary of $" + aSalesperson.getFixedSalary() + ".");
		System.out.println("Commissions are currently " + (aSalesperson.getPercentCommission() * 100) + "% of total sales.");
		System.out.println();

		
		System.out.println("You have earned $" + aSalesperson.totalCommission() + " in commissions.");
		System.out.println("Your Annual Compensation is $" + (aSalesperson.getFixedSalary() + aSalesperson.totalCommission()) + ".");
	}
}