Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net loss	$ (23,103)	$ (30,476)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	5,122	3,938
Provision for doubtful accounts	665	60
Net loss on disposal of assets	82	110
Non-cash interest expense	322	3,969
Stock-based compensation	4,955	3,159
Change in fair value of convertible preferred stock warrants	0	(520)
Changes in operating assets and liabilities:
Accounts receivable	(7,666)	(15,023)
Inventory	(4,549)	(5,422)
Prepayment to supplier	0	(5,000)
Prepaid expenses and other assets	(969)	(448)
Accounts payable, accrued and other liabilities	11,855	13,543
Deferred revenues	4,835	(20,164)
Net cash used in operating activities	(8,451)	(52,274)
Cash flows from investing activities:
Purchases of property and equipment	(4,886)	(11,054)
Net cash used in investing activities	(4,886)	(11,054)
Cash flows from financing activities:
Proceeds from term loans and debt	0	2,600
Repayments of term loans	(1,815)	(5,522)
Principal payments under capital leases	(40)	(96)
Proceeds from issuance of common stock under employee stock plans	1,672	47
Proceeds from issuance of common stock in IPO, net of underwriting discounts and commissions	0	58,609
Payment of offering costs	0	(2,032)
Net cash (used in) provided by financing activities	(183)	53,606
Effect of exchange rate changes on cash	4	(85)
Net (decrease) increase in cash and cash equivalents	(13,516)	(9,807)
Cash and cash equivalents—Beginning of period	45,294	51,524
Cash and cash equivalents—End of period	31,778	41,717
Supplemental disclosures of cash flow information:
Cash paid for interest	1,069	1,250
Noncash financing and investing activities:
Purchases of property and equipment included in accounts payable	302	412
Conversion of convertible notes into common stock upon IPO	0	21,204
Reclassification of convertible preferred stock warrant liability to additional paid-in capital upon IPO	$ 0	$ 879