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 sheet. 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 March 31, 2017 and March 31, 2016 are as follows:

	March 31, 2017			March 31, 2016
Balance at beginning of period	$	9,158		$	9,468
Accrued current period warranty expense		122			133
Payments and adjustments		(110	)		(104	)
Balance at end of period	$	9,170		$	9,497