Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Cash flows from operating activities
Net income (loss)	$ (836)	$ 155
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	335	161
Amortization of intangible assets	218	250
Loss on disposal of property and equipment	3	0
Bad debt expense	0	(9)
Inventory write-down	4	3
Stock-based compensation expense	317	153
Non-employee stock-based compensation expense	29	0
Change in fair value of warrant liability	1,706	467
Change in fair value of option liability	0	183
Changes in assets and liabilities
Accounts receivable	(45)	(2,498)
Other assets	(161)	(346)
Inventories	264	411
Prepaid expenses and other current assets	(757)	(733)
Other long term assets	10	0
Accounts payable	(1,942)	104
Accrued liabilities	(153)	(1,593)
Warranty reserve	245	(14)
Other long term liabilities	2	0
Deferred revenue	1,029	1,306
Net cash provided by (used in) operating activities	268	(2,000)
Cash flows from investing activities
Purchase of property and equipment	(545)	(398)
Net cash used in investing activities	(545)	(398)
Cash flows from financing activities
Principal payments on long-term borrowings	(500)	(405)
Payment for repurchase of common stock	(6)	0
Proceeds from exercise of stock options	288	820
Common stock issuance costs	(250)	0
Net cash provided by (used in) financing activities	(468)	415
Net decrease in cash and cash equivalents	(745)	(1,983)
Cash and cash equivalents at beginning of period	14,898	8,642
Cash and cash equivalents at end of period	14,153	6,659
Supplemental disclosure of non-cash investing and financing activities
Costs related to the initial public offering in accounts payable and accrued liabilities	1,988	0
Property and equipment in accounts payable and accrued liabilities	$ 116	$ 87