Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Cash flow from operating activities:
Net loss	$ (190)	$ (727)
Adjustments to reconcile net loss to net cash used for operating activities:
Depreciation	209	183
Amortization	373	430
Bad debt (benefit) provision	(14)	35
Gain from change in fair value of warrant	(1,136)	(431)
Loss on disposal of assets		25
Stock-based compensation expense	325	307
Amortization of debt discount and debt costs	183	198
Interest on settlement obligations	52	75
Changes in operating assets and liabilities:
Accounts receivable	88	(521)
Inventory	(74)	346
Prepaid and other current assets	30	(63)
Accounts payable	(799)	(215)
Accrued expenses	(593)	(1,403)
Deferred revenue	(119)	592
Total adjustments	(1,475)	(442)
Net cash used for operating activities	(1,665)	(1,169)
Cash flow from investing activities:
Additions to patents, technology and other	(15)	(2)
Additions to property and equipment	(202)	(97)
Net cash used for investing activities	(217)	(99)
Cash flow from financing activities:
Issuance of common stock for cash, net	28,243
Stock option exercises	287
Taxes paid related to restricted stock issuance	(101)	(7)
Payments of capital lease obligations	(32)
Net cash provided by (used for) financing activities	28,397	(7)
Increase (decrease) in cash and equivalents	26,515	(1,275)
Cash and equivalents, beginning of period	11,880	13,948
Cash and equivalents, end of period	38,395	12,673
Supplemental disclosure of cash flow information:
Interest paid	483	499
Taxes paid	$ 56	$ 25