INCOME TAXES - (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Summary of the loss before benefit from income taxes

The following table summarizes the income (loss) before income tax (benefit) expense:

	Year Ended   December 31,
	2017			2016			2015
United States	$	(39,088	)	$	(29,885	)	$	(28,830	)
Foreign	469			(11,701		)	(10,194		)
Total	$	(38,619	)	$	(41,586	)	$	(39,024	)

Summary of benefit from income taxes

The income taxes (benefit) expense is as follows:

	Year Ended   December 31,
	2017			2016			2015
Current:
Federal	$	—		$	—		$	—
State	163			106			166
Foreign	20			(8		)	26
Deferred:
Federal	808			(6,572		)	(10,179		)
State	(4,039		)	(772		)	(963		)
Foreign	(2,034		)	(1,273		)	(536		)
Change in valuation allowance	3,608			8,593			11,678
Income taxes (benefit) expense	$	(1,474	)	$	74		$	192

Summary of deferred tax liabilities

The following table summarizes net deferred liability which consists of the following:

	December 31,
	2017			2016
Net operating losses	$	42,703		$	38,234
Capital lease obligations	9,096			13,600
Income tax credits	3,647			3,030
Inventory	6,710			8,080
Stock-based compensation	3,249			4,668
Intellectual property agreements	2,420			3,123
Other deferred temporary differences	1,070			3,055
Deferred tax assets	68,895			73,790
Valuation allowance	(58,831		)	(55,223		)
Total deferred tax assets, net of valuation allowance	10,064			18,567
Capital lease assets	(7,655		)	(11,949		)
Intangible assets	(3,406		)	(7,472		)
Discount on convertible notes	(2,363		)	(4,163		)
Deferred tax liability	(13,424		)	(23,584		)
Net deferred tax liability	$	(3,360	)	$	(5,017	)

Summary of reconciliation for effective tax rate

The following table summarizes a reconciliation of the U.S. statutory federal income tax rate to our effective tax rate, as a percentage of loss before income tax benefit (expense) for the years ended December 31, 2017, 2016 and 2015:

	Year Ended   December 31,
	2017		2016		2015
Federal tax at statutory rates	34.0	%	34.0	%	34.0	%
State taxes, net of federal benefit	3.9		2.1		1.9
Tax credits	1.6		1.4		1.2
Permanent difference	2.3		(0.6	)	(0.9	)
Foreign income taxes	0.2		(2.9	)	(2.2	)
Change in valuation allowance	(59.7	)	(30.7	)	(29.9	)
Effect of statutory tax rate change	4.3		(1.4	)	(1.2	)
Adjustment to net operating loss deferred tax asset	13.0		—		—
Other adjustments	4.2		(2.1	)	(3.4	)
Income tax benefit (expense)	3.8	%	(0.2	)%	(0.5	)%

Summary of deferred tax asset valuation allowance

The following reflects a rollforward of the deferred tax asset valuation allowance for the years ended December 31, 2017, 2016 and 2015:

	Year Ended   December 31,
	2017			2016			2015
Beginning	$	(55,223	)	$	(46,630	)	$	(34,952	)
Increase to allowance	(3,608		)	(8,593		)	(11,678		)
Ending	$	(58,831	)	$	(55,223	)	$	(46,630	)