Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash Flows From Operating Activities
Net loss	$ (74,014)	$ (396,213)	$ (254,411)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	106,083	28,825	16,919
Stock-based compensation	80,737	50,145	29,419
Amortization of discount on convertible debt	9,143
Inventory write-downs	8,648	4,929	1,828
Write-off of Department of Energy (DOE) loan origination costs	5,558
Change in fair value of DOE warrant liability	(10,692)	1,854	2,750
Other non-cash operating activities	3,611	1,560	233
Foreign currency transaction gain	3,655
Changes in operating assets and liabilities
Accounts receivable	(21,917)	(17,303)	(2,829)
Inventories and operating lease vehicles	(463,270)	(194,726)	(13,638)
Prepaid expenses and other current assets	(17,466)	1,121	(248)
Other assets	(342)	(482)	(288)
Accounts payable	(243)	187,821	19,891
Accrued liabilities	66,837	9,603	10,620
Deferred revenue	268,153	(526)	(1,927)
Customer deposits	24,243	47,056	61,006
Resale value guarantee	236,299
Other long-term liabilities	32,971	10,255	2,641
Net cash provided by (used in) operating activities	257,994	(266,081)	(128,034)
Cash Flows From Investing Activities
Purchases of property and equipment excluding capital leases	(264,224)	(239,228)	(184,226)
Withdrawals out of our dedicated Department of Energy account, net	14,752	8,620	50,121
(Increase) decrease in other restricted cash	55	(1,330)	(3,201)
Purchases of marketable securities		(14,992)	(64,952)
Maturities of short-term marketable securities		40,000	40,000
Net cash used in investing activities	(249,417)	(206,930)	(162,258)
Cash Flows From Financing Activities
Proceeds from convertible debt	660,000
Proceeds from issuance of common stock in public offering	360,000	221,496	172,410
Proceeds from issuance of warrants	120,318
Proceeds from exercise of stock options and other stock issuances	95,307	24,885	10,525
Proceeds from issuance of common stock in private placement	55,000		59,058
Principal payments on DOE loans	(452,337)	(12,710)
Purchase of convertible note hedges	(177,540)
Common stock and convertible debt issuance costs	(16,901)
Principal payments on capital leases and other debt	(8,425)	(2,832)	(416)
Proceeds from DOE loans		188,796	204,423
Net cash provided by financing activities	635,422	419,635	446,000
Net increase (decrease) in cash and cash equivalents	643,999	(53,376)	155,708
Cash and cash equivalents at beginning of period	201,890	255,266	99,558
Cash and cash equivalents at end of period	845,889	201,890	255,266
Supplemental Disclosures
Interest paid	9,041	6,938	3,472
Income taxes paid	257	117	282
Supplemental noncash investing activities
Acquisition of property and equipment	$ 38,789	$ 44,890	$ 15,592