Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities
Net loss	$ (21,288)	$ (8,623)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	2,231	1,798
Change in non-cash interest income, net	(5)	(52)
Loss on disposal of property and equipment	77	0
Allowance for doubtful accounts	8	14
Inventory write-down	297	136
Change in lease-related performance liabilities	(432)	(104)
Stock-based compensation expense	8,160	6,113
Changes in operating assets and liabilities:
Accounts receivable	7,759	1,424
Other receivables	14	(508)
Inventories	1,138	(2,161)
Prepaid expenses and other assets	(971)	2
Accounts payable	(1,045)	47
Accrued payroll and other liabilities	621	(3,121)
Deferred revenue	(430)	1,715
Net cash used in operating activities	(3,866)	(3,320)
Cash flows from investing activities
Purchase of property and equipment	(1,598)	(3,484)
Business acquisitions, net of cash acquired	(6,950)	0
Purchase of short-term investments	(87,342)	(113,199)
Maturities of short-term investments	70,747	41,290
Sales of short-term investments	3,924	0
Changes in Restricted Cash	(265)	0
Net cash used in investing activities	(20,954)	(75,393)
Cash flows from financing activities
Cash from lease-related performance obligations	565	743
Payment for repurchase of early exercised options	(12)	(14)
Proceeds from issuance of common stock from the employee stock purchase plan	945	2,572
Proceeds from exercise of stock options	874	1,426
Tax withholdings paid on behalf of employees for net share settlement	(1,020)	(476)
Proceeds from exercise of common stock warrants	0	226
Net cash provided by financing activities	1,352	4,477
Net decrease in cash and cash equivalents	(23,468)	(74,236)
Cash and cash equivalents at beginning of period	39,652	92,521
Cash and cash equivalents at end of period	16,184	18,285
Supplemental disclosure of non-cash investing and financing activities:
Property and equipment in accounts payable and accrued liabilities	$ 52	$ 112