Bill.com, which markets invoicing services, has closed a $50-million financing round. The company intends to use the proceeds to fuel growth on the heels of doubling its business in the last 12 months. The latest infusion of capital brings the amount it has raised to more than $100 million. Funds came from Silicon Valley Bank, which joined existing investors DCM Ventures, Scale Venture Partners, August Capital, Napier Park Global Capital, American Express Ventures and Commerce Ventures.