Balance sheet components (Tables)

12 Months Ended

Dec. 31, 2018

Balance Sheet Related Disclosures [Abstract]

Restricted Cash

Restricted cash was as follows (in thousands):

	December 31,
	2018		2017
Restricted in connection with notes payable and short-term borrowing (see Note 12)	$	2,589	$	537
Restricted in connection with asset purchase agreement (see Note 10)	2,019		2,121
Restricted in connection with a current legal dispute with APAT OE (See Note 10)	5,156		—
Restricted in connection with government grants received in advance	1,289		—
Total restricted cash	$	11,053	$	2,658
Reported as:
Restricted cash	$	11,053	$	2,658

Accounts Receivable, Net

Accounts receivable, net were as follows (in thousands): 

	December 31,
	2018			2017
Accounts receivable	$	74,343		$	65,499
Trade notes receivable	672			2,356
Allowance for doubtful accounts	(264		)	(626		)
	$	74,751		$	67,229

Summary of Movement in Allowance for Doubtful Accounts

The table below summarizes the movement in the Company’s allowance for doubtful accounts (in thousands): 

Balance at December 31, 2015	$	(843	)
Reversal of provision for bad debt	382
Write-offs, net of recoveries	36
Balance at December 31, 2016	(425		)
Provision for bad debt	(577		)
Write-offs, net of recoveries	376
Balance at December 31, 2017	(626		)
Reversal of provision for bad debt	428
Write-offs, net of recoveries	(66		)
Balance at December 31, 2018	$	(264	)

Inventories, net

Inventories were as follows (in thousands): 

	December 31,
	2018		2017
Raw materials	$	27,806	$	33,400
Work in process	13,044		13,246
Finished goods(1)	11,309		20,655
	$	52,159	$	67,301

(1) Included in finished goods was $5.6 million and $7.1 million of inventory at customer vendor managed inventory locations at December 31, 2018 and 2017, respectively. 

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets were as follows (in thousands):

	December 31,
	2018		2017
Prepaid taxes and taxes receivable	$	5,461	$	15,162
Transition services agreement receivable (see Note 10)	11,999		12,817
Deposits and other prepaid expenses	3,020		4,138
Other receivable	6,125		4,118
	$	26,605	$	36,235

Property, Plant and Equipment, Net

Property, plant and equipment, net were as follows (in thousands): 

	December 31,
	2018			2017
Land	$	3,157		$	3,083
Buildings	23,379			24,102
Machinery and equipment	187,746			189,527
Furniture, fixtures, software and office equipment	10,201			9,948
Leasehold improvements	22,000			26,007
	246,483			252,667
Less: Accumulated depreciation	(146,393		)	(125,102		)
	$	100,090		$	127,565

Accrued and Other Current Liabilities

Accrued and other current liabilities were as follows (in thousands): 

	December 31,
	2018		2017
Employee-related	$	14,899	$	12,990
Transition services agreement payables (see Note 10)	11,769		11,222
Asset sale related contingent liabilities (see Note 10)	6,751		7,135
Income and other taxes payable	1,580		542
Deferred revenue, current	1,114		939
Accrued warranty	672		1,334
Rusnano payment derivative	2,000		—
Accrued litigation settlement	2,645		—
Other accrued expenses	8,858		9,080
	$	50,288	$	43,242

Accrued Warranty

The table below summarizes the movement in the warranty accrual, which is included in accrued and other current liabilities (in thousands): 

	Years ended December 31,
	2018			2017			2016
Beginning balance	$	1,334		$	678		$	1,175
Warranty accruals	399			1,263			102
Settlements	(1,061		)	(607		)	(599		)
Ending balance	$	672		$	1,334		$	678

Other Noncurrent Liabilities

Other noncurrent liabilities were as follows (in thousands): 

	December 31,
	2018		2017
Pension and other employee-related	$	4,529	$	4,675
Deferred rent	3,058		2,908
Deferred revenue	—		617
Government grant	2,108		1,095
Rusnano payment derivative	—		389
Deferred income tax liabilities	—		106
Capital lease obligation	282		—
Asset retirement obligations and other	3,522		4,285
	$	13,499	$	14,075