James Alexander shall invoice Aclaris concurrently with any shipment of the Drug Product and Aclaris shall make full payment to James Alexander at the address specified on the invoice, no later than thirty (30) calendar days from the date of receipt of the invoice.  If Aclaris has not made payment in full by the expiration of such thirty (30) day period, James Alexander shall be entitled to interest on such unpaid amount equal to [***] per month for any unpaid amounts.