Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities
Net income	$ 12,158	$ 13,934
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,053	586
Write-down of inventory to net realizable value	2,953	192
Change in fair value of convertible preferred stock warrants	290	556
Stock-based compensation	2,190	784
Loss on disposal of property and equipment	20
Amortization/accretion of marketable securities	28
Non-cash rent expense	148
Changes in assets and liabilities:
Accounts receivable	(4,775)	(1,810)
Inventories	5,751	(4,435)
Prepaid expenses and other assets	(1,784)	(742)
Accounts payable	(1,747)	1,011
Accrued and other liabilities	2,879	2,081
Deferred credits and income	(284)	385
Net cash provided by operating activities	18,880	12,542
Cash flows from investing activities
Purchases of property and equipment	(3,715)	(1,299)
Purchases of marketable securities	(22,079)
Change in restricted cash		9
Net cash used in investing activities	(25,794)	(1,290)
Cash flows from financing activities
Proceeds from initial public offering, net of underwriting discounts and commissions	91,548
Proceeds from exercise of preferred stock warrants	400
Proceeds from exercise of stock options	512	247
Payment in connection with initial public offering costs	(3,723)	(156)
Repayment of equipment term loan	(102)	(103)
Net cash provided by financing activities	88,635	(12)
Effect of exchange rate change on cash and cash equivalents	31	(41)
Net increase in cash and cash equivalents	81,752	11,199
Cash and cash equivalents
Beginning of period	15,983	12,095
End of period	97,735	23,294
Supplemental disclosure of noncash financing activities
Noncash obligation for property, plant and equipment	630
Conversion of convertible preferred stock to common stock	74,348
Conversion of preferred stock warrants to common stock warrants	$ 23