The courts will usually excuse an employee from jury duty if the company can demonstrate extreme hardship. Merely being inconvenienced is not enough justification for most courts, however. If the employee refuses to apply for an exemption, there isn't really much a company can do about it, unless the absence could cause the company irreparable harm. On the other hand, a company can get in a lot of trouble if it tries to discharge, discriminate, or retaliate against employees because of jury duty.
Some states have their own laws protecting employees from retaliation and specifying payment.
Remember these tips when an employee is called for jury duty. Inform employees about their obligation to the company once they've been summoned. Keep in mind that employees did not volunteer for jury duty. Don't threaten them as if they were going on an extended vacation. Make sure the employees understand any obligation they have to report to work when released early or when not required for court duty.