DETAILS OF CERTAIN BALANCE SHEET ACCOUNTS

Accounts receivable, net:



	March 31,
(in thousands)	2015			2016
Accounts receivable	$	159,397		$	163,834
Provisions for returns	(6,194		)	(7,314		)
Provisions for promotions and rebates	(15,401		)	(27,737		)
Provisions for doubtful accounts and sales allowances	(1,221		)	(564		)
Accounts receivable, net	$	136,581		$	128,219

Inventory, net:



	March 31,
(in thousands)	2015		2016
Raw materials	$	24,263	$	21,612
Work in process	1,653		1,642
Finished goods	30,760		29,908
Inventory, net	$	56,676	$	53,162

Property, plant, and equipment, net:



	March 31,
(in thousands)	2015			2016
Land	$	16,666		$	16,666
Buildings and improvements (useful life: 7-30 years)	99,914			101,265
Machinery and equipment (useful life: 2-10 years)	103,344			105,532
Software (useful life: 5-10 years)	43,387			49,603
Construction in progress	8,679			20,119
	271,990			293,185
Accumulated depreciation and amortization	(132,577		)	(143,450		)
Property, plant, and equipment, net	$	139,413		$	149,735

Depreciation and amortization expense for fiscal years 2016, 2015, and 2014 was $19.9 million, $18.5 million, and $15.5 million, respectively.

Included in Software are unamortized capitalized software costs relating to both purchased and internally developed software of $21.8 million and $19.2 million at March 31, 2016 and 2015, respectively. Amortization expense related to capitalized software costs in fiscal years 2016, 2015, and 2014 was $4.1 million, $3.8 million, and $2.3 million, respectively.

Included in Construction in progress at March 31, 2016 was $9.2 million in costs related to the construction of a new smarter working office for our European headquarters in the Netherlands, $3.0 million in costs related to the implementation of a manufacturing execution system at our facility in Mexico, as well as costs associated with building and leasehold improvements at our U.S. headquarters, tooling for new products, and other IT-related expenditures.

Accrued liabilities:



	March 31,
(in thousands)	2015		2016
Employee compensation and benefits	$	31,888	$	22,955
Accrued interest on 5.50% Senior Notes	—		10,501
Warranty obligation	7,717		8,537
VAT/Sales Tax Payable	4,749		4,894
Restructuring and other related charges⁽¹⁾	—		5,783
Accrued other	17,687		17,364
Accrued liabilities	$	62,041	$	70,034

⁽¹⁾ Refer to Note 11, Restructuring and Other Related Charges, for more information on the Company's restructuring activity.

Changes in the warranty obligation, which are included as a component of accrued liabilities in the consolidated balance sheets, are as follows:



	Year ended March 31,
(in thousands)	2015			2016
Warranty obligation at beginning of year	$	7,965		$	7,717
Warranty provision related to products shipped	9,955			9,125
Deductions for warranty claims processed	(8,856		)	(9,075		)
Adjustments related to preexisting warranties	(1,347		)	770
Warranty obligation at end of year	$	7,717		$	8,537