Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

Schedule of Activity Related to Resale Value Guarantee Program

Activity related to our resale value guarantee program consisted of the following for the period presented (in thousands):

	Year ended			Year ended
	December 31, 2015			December 31, 2014
Operating Lease Vehicles
Operating lease vehicles—beginning of period	$	684,590		$	376,979
Net increase in operating lease vehicles		1,047,220			380,627
Depreciation expense recorded in cost of automotive revenues		(130,355	)		(63,105	)
Additional depreciation expense recorded in cost of automotive revenues as a result of early cancellation of resale value guarantee		(21,487	)		(9,251	)
Increases to inventory from vehicles returned under our trade- in program		(23,439	)		(660	)
Operating lease vehicles—end of period	$	1,556,529		$	684,590

Deferred Revenue
Deferred revenue—beginning of period	$	381,096		$	230,856
Net increase in deferred revenue from new vehicle deliveries and reclassification of collateralized borrowing from long- term to short-term		553,765			280,542
Amortization of deferred revenue and short-term collateralized borrowing recorded in automotive revenue		(229,624	)		(118,570	)
Additional revenue recorded in automotive revenue as a result of early cancellation of resale value guarantee		(12,352	)		(9,590	)
Recognition of deferred revenue resulting from return of vehicle under trade-in program		(13,753	)		(2,142	)
Deferred revenue—end of period	$	679,132		$	381,096
Resale Value Guarantee
Resale value guarantee liability—beginning of period	$	487,880		$	236,298
Net increase in resale value guarantee		1,013,733			262,526
Reclassification from long-term to short-term collateralized borrowing		(29,612	)		—
Additional revenue recorded in automotive revenue as a result of early cancellation of resale value guarantee		(11,042	)		(8,557	)
Release of resale value guarantee resulting from return of vehicle under trade-in program		(30,386	)		(2,387	)
Resale value guarantee liability—end of period	$	1,430,573		$	487,880

Summary of Accounts Receivable from Customers in Excess of 10% of Total Accounts Receivable

The following summarizes the accounts receivable from our customers in excess of 10% of our total accounts receivable:

	December 31,			December 31,
	2015			2014
Customer A		15	%		7	%
Customer B		8	%		14	%
Customer C		6	%		13	%
Customer D		—			19	%

Schedule of Estimated Useful Lives of Related Assets

Property, plant and equipment are recognized at cost less accumulated depreciation. Depreciation is generally computed using the straight-line method over the estimated useful lives of the related assets as follows:

Machinery, equipment and office furniture		3 to 12 years
Building and building improvements		30 years
Computer equipment and software		3 years

Schedule of Accrued Warranty Activity

Accrued warranty activity consisted of the following for the periods presented (in thousands):

	Year Ended December 31,
	2015			2014			2013
Accrued warranty—beginning of period	$	129,043		$	53,182		$	13,013
Warranty costs incurred		(52,760	)		(39,903	)		(19,160	)
Net changes in liability for pre-existing warranties, including expirations		1,470			18,599			(2,072	)
Provision for warranty		103,001			97,165			61,401
Accrued warranty—end of period	$	180,754		$	129,043		$	53,182

Schedule of Potential Weighted Common Shares Outstanding that were Excluded from Computation of Basic and Diluted Net Loss per Share of Common Stock

The following table presents the potential weighted common shares outstanding that were excluded from the computation of basic and diluted net loss per share of common stock for the periods, related to the following securities:

	Year Ended December 31,
	2015		2014		2013
Employee share based awards		15,592,736		14,729,749		13,904,875
Convertible senior notes		2,431,265		2,344,998		411,560
Warrants issued May 2013		1,049,791		921,985		—
DOE warrant		—		—		1,061,439