(9) Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consist of the following at:



	January 31, 2013		July 31, 2012
Accrued wages and benefits	$	9,068,000	16,467,000
Accrued warranty obligations (see below)	8,664,000		7,883,000
Accrued commissions and royalties	5,009,000		3,946,000
Accrued business acquisition payments (see below)	375,000		1,752,000
Other	7,702,000		10,822,000
Accrued expenses and other current liabilities	$	30,818,000	40,870,000

Accrued Warranty Obligations

We provide warranty coverage for most of our products for a period of at least one year from the date of shipment. We record a liability for estimated warranty expense based on historical claims, product failure rates and other factors. Some of our product warranties are provided under long-term contracts, the costs of which are incorporated into our estimates of total contract costs.

Changes in our product warranty liability were as follows:



	Six months ended January 31,
	2013			2012
Balance at beginning of period	$	7,883,000		9,120,000
Provision for warranty obligations	3,709,000			3,194,000
Charges incurred	(2,928,000		)	(3,462,000	)
Balance at end of period	$	8,664,000		8,852,000

Accrued Business Acquisition Payments

In October 2010, we acquired the WAN optimization technology assets and assumed certain liabilities of Stampede for an estimated total purchase price of approximately $5,303,000. Almost all of the purchase price for Stampede was allocated to the estimated fair value of technologies acquired and was assigned an estimated amortizable life of five years. As of January 31, 2013, we maintain a liability of approximately $375,000 for contingent earn-out payments we expect to make, through October 1, 2013, based on the likelihood that certain revenue and related gross margin milestones will be met in future periods. We review our estimates and updated forecasts on a quarterly basis and record adjustments as required. In fiscal 2013, we recorded a benefit of $889,000 and $3,267,000 related to a change in fair value of the earn-out liability, which is reflected as a reduction to selling, general and administrative expenses in our Condensed Consolidated Statement of Operations for the three and six months ended January 31, 2013, respectively. There was no change in the fair value of the earn-out liability during the three and six months ended January 31, 2012.

Interest accreted on the contingent earn-out liability for the three and six months ended January 31, 2013 and 2012 was $25,000 and $133,000, respectively, and $119,000 and $241,000, respectively, and total interest accreted through January 31, 2013 was $986,000. As of January 31, 2013, we paid $1,729,000 of the total purchase price in cash, including $229,000 of earn-out payments.