Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating activities:
Net loss	$ (83,132)	$ (53,901)	$ (16,280)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	3,519	1,707	786
Loss on disposal of property and equipment		46
Net amortization of premiums on marketable securities	2,494	1,882	604
Amortization of debt discount	144	109	60
Amortization of loan fees		13
Noncash interest income, net		(4)	(45)
Issuance of common stock warrant in connection with professional services rendered			6
Issuance of common stock in connection with professional services rendered		16
Stock-based compensation expense	15,356	10,907	1,952
Loss from equity method investment	1,824
Revaluation of warrant liability	(2,284)	3,637	2,638
Changes in operating assets and liabilities:
Accounts receivable	749	(3,359)	2,876
Unbilled revenue	739	(422)	(3,467)
Inventories	(3,762)	(3,129)
Prepaid expenses and other current assets	611	(2,298)	(974)
Other assets	2	69	(164)
Accounts payable	(1,396)	3,025	2,035
Accrued liabilities	9	5,183	2,214
Deferred revenue	(2,722)	1,651	(1,075)
Other current and long-term liabilities	278	(37)	525
Net cash used in operating activities	(67,571)	(34,905)	(8,309)
Investing activities:
Purchases of property, plant and equipment	(12,554)	(15,502)	(2,505)
Proceeds received from the sale of equipment		290
Purchases of marketable securities	(64,908)	(240,298)	(57,221)
Maturities of marketable securities	130,682	58,866	21,544
Proceeds from sales of marketable securities	29,014	13,863	654
Capital contribution in unconsolidated joint venture	(10,000)
Restricted cash		(50)	(159)
Net cash provided by (used in) investing activities	72,234	(182,831)	(37,687)
Financing activities:
Repayments under loan agreements	(5,408)	(333)	(1,870)
Proceeds from the issuance of convertible preferred stock			60,000
Payment for equity financing costs		(3,868)	(286)
Proceeds from the issuance of common stock, net of repurchases	1,737	866	644
Proceeds from issuance of common stock, pursuant to ESPP	1,161
Early exercise of stock options subject to repurchase	(60)	(105)	160
Payments received on promissory notes to stockholders		1,601
Proceeds from borrowings under loan agreements		15,000
Payment for loan costs and fees		(90)
Proceeds from exercise of common and preferred stock warrants		37
Proceeds from issuance of common stock in initial public offering, net of underwriting discounts and commission		201,236
Net cash (used in) provided by financing activities	(2,570)	214,344	58,648
Effect of exchange rate changes on cash and cash equivalents	(55)	(325)
Net increase (decrease) of cash and cash equivalents	2,038	(3,717)	12,652
Cash and cash equivalents-beginning of period	28,780	32,497	19,845
Cash and cash equivalents-end of period	30,818	28,780	32,497
Supplemental disclosures of cash flow information:
Interest paid in cash	409	452	182
Income taxes paid in cash
Supplemental disclosure of noncash investing and financing activities:
Accretion of redeemable convertible preferred stock		60	140
Capital assets in accounts payable and accrued liabilities	421	3,103	1,313
Accrued offering costs		428
Debt issue costs in accounts payable and accrued liabilities	148
Addition of land, building and equipment under notes payable		5,248	265
Change in unrealized gain (loss) on investments	642	(276)	(40)
Conversion of convertible preferred stock to common stock upon initial public offering		128,374
Reclassification of warrant liability to additional paid-in capital	4,586	6,598
Reclassification of deferred offering costs to additional paid-in capital upon initial public offering		4,295
Warrant issued for investment in unconsolidated joint venture	10,361
Capital contribution to unconsolidated joint venture settled with reduction of receivable from unconsolidated joint venture	$ 511