10. Warranty Costs

The contractual warranty period of the Company's products generally ranges from three months to two years with certain warranties extending for longer periods. Estimated expenses related to product warranties are accrued at the time products are sold to customers and are recorded in accruals and other current liabilities on the unaudited condensed consolidated balance sheets. Estimates are established using historical information as to the nature, frequency and average costs of warranty claims. Changes in the carrying amount of accrued product warranty costs for each of the quarters ended September 30, 2018 and 2017 are as follows:

	September 30, 2018			September 30, 2017
Balance at beginning of period	$	7,479		$	9,158
Accrued current period warranty expense		99			511
Payments and adjustments		(2,049	)		(2,047	)
Balance at end of period	$	5,529		$	7,622