Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flows from operating activities:
Net loss	$ (6,236)	$ (10,406)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,910	1,660
Provision for doubtful accounts	26	0
Net loss on disposal of assets	6	0
Non-cash interest expense	102	108
Stock-based compensation	2,013	1,435
Changes in operating assets and liabilities:
Accounts receivable	3,608	2,835
Inventory	2,467	(2,466)
Prepaid expenses and other assets	(977)	(355)
Accounts payable, accrued compensation and other accrued liabilities	1,159	(3,316)
Warranty obligations	296	2,557
Deferred revenues	(93)	976
Net cash provided by (used in) operating activities	4,281	(6,972)
Cash flows from investing activities:
Purchases of property and equipment	(2,172)	(1,682)
Net cash used in investing activities	(2,172)	(1,682)
Cash flows from financing activities:
Repayments of term loans	(866)	(591)
Principal payments under capital leases	0	(40)
Proceeds from issuance of common stock under employee stock plans	454	603
Net cash used in financing activities	(412)	(28)
Effect of exchange rate changes on cash	48	(178)
Net increase (decrease) in cash and cash equivalents	1,745	(8,860)
Cash and cash equivalents—Beginning of period	38,190	45,294
Cash and cash equivalents—End of period	39,935	36,434
Supplemental disclosures of non-cash investing and financing activities:
Purchases of property and equipment included in accounts payable	$ 497	$ 490