P10 Industries (PIOE) 10-K 4 Mar 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Feb. 20, 2014	Jun. 30, 2013
Document and Entity Information [Abstract]	'	'	'
Entity Registrant Name	'ACTIVE POWER INC	'	'
Entity Central Index Key	'0001044435	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Well-known Seasoned Issuer	'No	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Filer Category	'Accelerated Filer	'	'
Entity Public Float	'	'	$64.10
Entity Common Stock, Shares Outstanding	'	19,403,706	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Document Type	'10-K	'	'
Amendment Flag	'false	'	'
Document Period End Date	31-Dec-13	'	'

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$12,261	$13,524
Restricted cash	520	0
Accounts receivable, net of allowance for doubtful accounts of $313 and $488 at December 31, 2013 and December 31, 2012, respectively	9,075	17,862
Inventories, net	12,020	11,079
Prepaid expenses and other	680	567
Total current assets	34,556	43,032
Property and equipment, net	3,056	2,458
Deposits and other	295	309
Total assets	37,907	45,799
Current liabilities:	'	'
Accounts payable	2,993	4,036
Accrued expenses	5,583	4,948
Deferred revenue	2,749	4,568
Revolving line of credit	5,535	5,535
Total current liabilities	16,860	19,087
Long term liabilities	741	713
Stockholders' equity:	'	'
Preferred stock - $0.001 par value; 2,000 shares authorized	0	0
Common stock - $0.001 par value; 30,000 shares authorized; 19,452 and 19,171 issued and 19,388 and 19,125 outstanding at December 31, 2013 and December 31, 2012, respectively	19	19
Treasury stock	-215	-144
Additional paid-in capital	290,964	288,619
Accumulated deficit	-271,168	-262,817
Other accumulated comprehensive income	706	322
Total stockholders' equity	20,306	25,999
Total liabilities and stockholders' equity	$37,907	$45,799

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, except Share data, unless otherwise specified
Current assets:	'	'
Accounts receivable, allowance for doubtful accounts	$313	$488
Stockholders' equity:	'	'
Preferred Stock, par value (in dollars per share)	$0.00	$0.00
Preferred stock authorized (in shares)	2,000,000	2,000,000
Common Stock, par value (in dollars per share)	$0.00	$0.00
Common Stock, shares authorized (in shares)	30,000,000	30,000,000
Common Stock, shares issued (in shares)	19,452,000	19,171,000
Common Stock, shares outstanding (in shares)	19,388,000	19,125,000

Consolidated_Statement_of_Oper

Consolidated Statement of Operations and Comprehensive Loss (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues:	'	'	'
Product revenue	$44,158	$62,031	$62,650
Service and other revenue	17,541	14,284	12,832
Total revenue	61,699	76,315	75,482
Cost of goods sold:	'	'	'
Cost of product revenue	32,825	42,510	47,664
Cost of service and other revenue	9,478	9,091	9,917
Total cost of goods sold	42,303	51,601	57,581
Gross profit	19,396	24,714	17,901
Operating expenses:	'	'	'
Research and development	7,430	5,440	4,739
Selling and marketing	12,032	14,139	13,812
General and administrative	7,551	6,861	6,230
Total operating expenses	27,013	26,440	24,781
Loss from Operations	-7,617	-1,726	-6,880
Interest expense, net	-370	-327	-225
Other income (expense), net	-364	131	11
Net Loss	-8,351	-1,922	-7,094
Net Loss per share, basic and diluted (in dollars per share)	($0.43)	($0.10)	($0.44)
Shares used in computing net loss per share, basic and diluted (in shares)	19,329	18,584	16,104
Comprehensive loss:	'	'	'
Net Loss	-8,351	-1,922	-7,094
Translation gain on subsidiaries denominated in foreign currencies	384	123	360
Comprehensive loss	($7,967)	($1,799)	($6,734)

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders' Equity (USD $)	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Other Accumulated Comprehensive Income (Loss) [Member]	Total
In Thousands, except Share data, unless otherwise specified
Balance at Dec. 31, 2010	$16	($103)	$274,871	($253,801)	($161)	$20,822
Balance (in shares) at Dec. 31, 2010	15,972,000	24,000	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'
Employee stock option exercises	0	0	510	0	0	510
Employee stock option exercises (in shares)	144,000	0	'	'	'	'
Shares held in treasury	0	-12	'	0	0	-12
Shares held in treasury (in shares)	0	4,000	'	'	'	'
Net translation gain on foreign subsidiaries	0	0	0	0	360	360
Stock-based compensation	0	0	1,706	0	0	1,706
Net Loss	0	0	0	-7,094	0	-7,094
Balance at Dec. 31, 2011	16	-115	277,087	-260,895	199	16,292
Balance (in shares) at Dec. 31, 2011	16,116,000	28,000	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'
Employee stock option exercises	0	0	562	0	0	562
Employee stock option exercises (in shares)	155,000	0	'	'	'	'
Sale of common stock, net of issuance costs	3	0	9,560	0	0	9,563
Sale of common stock, net of issuance costs (in shares)	2,868,000	0	'	'	'	'
Release of Restricted Stock	0	0	0	0	0	0
Release of Restricted Stock (in shares)	32,000	0	'	'	'	'
Shares held in treasury	0	-29	0	0	0	-29
Shares held in treasury (in shares)	0	5,000	'	'	'	'
Net translation gain on foreign subsidiaries	0	0	0	0	123	123
Stock-based compensation	0	0	1,410	0	0	1,410
Net Loss	0	0	0	-1,922	0	-1,922
Balance at Dec. 31, 2012	19	-144	288,619	-262,817	322	25,999
Balance (in shares) at Dec. 31, 2012	19,171,000	33,000	'	'	'	'
Increase (Decrease) in Stockholders' Equity [Roll Forward]	'	'	'	'	'	'
Employee stock option exercises	0	0	711	0	0	711
Employee stock option exercises (in shares)	200,000	0	'	'	'	'
Release of Restricted Stock	0	0	4	0	0	-67
Release of Restricted Stock (in shares)	81,000	0	'	'	'	'
Shares held in treasury	'	-71	'	'	'	'
Shares held in treasury (in shares)	'	18,000	'	'	'	'
Net translation gain on foreign subsidiaries	0	0	0	0	384	384
Stock-based compensation	0	0	1,689	0	0	1,689
Issuance costs, shelf registration	'	'	-59	'	0	-59
Net Loss	0	0	0	-8,351	0	-8,351
Balance at Dec. 31, 2013	$19	($215)	$290,964	($271,168)	$706	$20,306
Balance (in shares) at Dec. 31, 2013	19,452,000	51,000	'	'	'	'

Consolidated_Statement_of_Cash

Consolidated Statement of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities	'	'	'
Net Loss	($8,351)	($1,922)	($7,094)
Adjustments to reconcile net loss to cash provided by (used in) operating activities:	'	'	'
Depreciation expense	1,084	1,282	1,383
Change to allowance for doubtful accounts	-175	151	9
Loss on disposal of fixed assets	30	-35	154
Impairment on fixed assets	69	218	8
Stock-based compensation	1,700	1,410	1,706
Changes in operating assets and liabilities:	'	'	'
Restricted cash	-520	389	-389
Accounts receivable	8,962	-6,850	3,536
Inventories	-1,796	-1,640	-3,009
Prepaid expenses and other assets	-99	-58	7
Accounts payable	-1,043	-721	-1,265
Accrued expenses	623	-403	-1,717
Deferred revenue	-1,819	2,202	-126
Long term liabilities	28	-13	147
Net cash used in operating activities	-1,307	-5,990	-6,650
Investing activities	'	'	'
Sales/maturities of marketable securities	0	0	134
Purchases of property and equipment	-996	-1,274	-2,401
Proceeds from sale of fixed assets	71	212	0
Net cash used in investing activities	-925	-1,062	-2,267
Financing activities	'	'	'
Proceeds from private placement of common stock	0	9,750	0
Issuance costs of private placement	0	-187	0
Proceeds from draw on revolving line of credit	0	2,017	3,000
Payments on revolving line of credit	0	-2,017	0
Proceeds from employee stock option exercises	711	562	510
Issuance costs, shelf registration	-59	0	0
Taxes paid related to the net share settlement of equity awards	-67	-29	-12
Net cash provided by financing activities	585	10,096	3,498
Translation gain on subsidiaries in foreign currencies	384	123	360
Change in cash and cash equivalents	-1,263	3,167	-5,059
Cash and cash equivalents, beginning of period	13,524	10,357	15,416
Cash and cash equivalents, end of period	12,261	13,524	10,357
Supplemental Cash Flow Information:	'	'	'
Interest paid	$380	$335	$229

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Summary of Significant Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	1. Summary of Significant Accounting Policies
	Description of Business
	Active Power, Inc. and its subsidiaries (hereinafter referred to as “we”, “us”, “Active Power” or the “Company”) design, manufacture and sell our flywheel-based uninterruptible power supply (“UPS”) products and modular infrastructure solutions (“MIS”) which are designed to ensure continuity for data centers and other mission critical operations in the event of power disturbances. Our products and solutions are designed to deliver continuous conditioned (“clean”) power during power disturbances and outages, voltage surges and sags, and provide ride-through power in the event of a utility failure, supporting operations until utility power is restored or a longer term alternative power source, such as a diesel generator, is started. We sell our products globally through our direct sales force, manufacturer’s representatives, Original Equipment Manufacturer (“OEM”) channels and IT partners. Our current principal markets are the Americas, Europe Middle East and Africa (“EMEA”), and Asia.
	We were founded as a Texas Corporation in 1992 and reincorporated in Delaware in 2000 prior to our initial public offering. Our headquarters are in Austin, Texas with international offices in the UK, Germany and China.
	The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“US GAAP”) and include the accounts of the Company and its consolidated subsidiaries. All intercompany transactions and balances have been eliminated upon consolidation.
	The accompanying consolidated financial statements have also been prepared on the assumption that the Company will continue to operate as a going concern. Accordingly assets and liabilities are recorded on the basis that the Company will be able to realize its assets and discharge its liabilities in the normal course of business. The Company’s history of operating losses and use of cash, in the absence of other factors, may cause uncertainty as to its ability to continue as a going concern. We have reviewed the current and prospective sources of liquidity, significant conditions and events and forecast financial results and concluded that we have adequate resources to continue to operate as a going concern. Our business plan and our assumptions around the adequacy of our liquidity are based on estimates regarding expected revenues and future costs. However, our revenues may not meet our projections or our costs may exceed our estimates. Further, our estimates may change and future events or developments may also affect our estimates. Any of these factors may change our expectation of cash usage in 2014 or significantly affect our level of liquidity, which may require us to seek additional financing or take other measures to reduce our operating costs in order to continue operating. These financial statements do not include any adjustments that might result from the Company not being able to continue as a going concern.
	All common stock information and related share prices included in these notes to financial statements have been adjusted to reflect the five for one reverse stock split that occurred on December 21, 2012.
	As previously disclosed in its September 5, 2013 press release and Form 8-K, the Company announced in error in April 2013 that it had entered into a strategic distribution agreement in China with Digital China Information Service Company Limited (“Digital China”). The actual party to this agreement is Qiyuan Network System Limited (“Qiyuan”). A Company employee in China represented to management that Qiyuan was a subsidiary of Digital China. Management subsequently discovered that the Company employee in China intentionally misrepresented the relationship between Qiyuan and Digital China. Qiyuan has no affiliation with Digital China. Due to this discovery, we restated our first quarter 2013 and second quarter 2013 results on Form 10-Q/A.
	Use of Estimates
	The preparation of financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. Changes in the estimates or assumptions used by management could have a material impact upon reported amounts and our results of operations.
	Revenue Recognition
	In general, we recognize revenue when four criteria are met: (i) persuasive evidence that an arrangement exists; (ii) delivery has occurred or services have been rendered; (iii) the sales price is fixed or determinable; and (iv) collectability is reasonably assured. In general, revenue is recognized when revenue-generating transactions generally fall into one of the following categories of revenue recognition:
		●	We recognize product revenue at the time of shipment for a significant portion of all products sold directly to customers and through distributors because title and risk of loss pass on delivery to the common carrier. Our customers and distributors do not have the right to return products. If title and risk of loss pass at some other point in time, we recognize such revenue for our customers when the product is delivered to the customer and title and risk of loss has passed. We may enter into bill-and-hold arrangements and when this happens delivery may not be occur, but other criteria are reviewed to determine proper timing of revenue recognition.
		●	We recognize installation, service and maintenance revenue at the time the service is performed.
		●	We recognize revenue associated with extended maintenance agreements (“EMAs”) over the life of the contracts using the straight-line method, which approximates the expected timing in which applicable services are performed. Amounts collected in advance of revenue recognition are recorded as a current liability in the deferred revenue line of the consolidated balance sheet or long-term liability based on the time from the balance sheet date to the future date of revenue recognition.
		●	We recognize revenue on certain rental programs over the life of the rental agreement using the straight-line method. Amounts collected in advance of revenue recognition are recorded as a current or long-term liability based on the time from the balance sheet date to the future date of revenue recognition.
		●	Shipping costs reimbursed by the customer are included in revenue.
	When collectability is not reasonably assured, we defer revenue and will recognize revenue on a cost recovery basis as payments are received.
	Multiple element arrangements (“MEAs”) are arrangements to sell products to customers frequently include multiple deliverables. Our most significant MEAs include the sale of one or more of our CleanSource UPS or CleanSource PowerHouse products, combined with one or more of the following products: design services, project management, commissioning and installation services, spare parts or consumables, and EMA’s. Delivery of the various products or performance of services within the arrangement may or may not coincide. Certain services related to design and consulting may occur prior to delivery of product and commissioning and installation typically take place within six months of product delivery, depending upon customer requirements. EMAs, consumables, and repair, maintenance or consulting services generally are delivered over a period of one to five years. In certain arrangements revenue recognized is limited to the amount invoiced or received that is not contingent on the delivery of future products and services.
	When arrangements include multiple elements, we allocate revenue to each element based on the relative selling price and recognize revenue when the elements have standalone value and the four criteria for revenue recognition have been met. We establish the selling price of each element based on Vendor Specific Objective Evidence (“VSOE”) if available, Third Party Evidence (“TPE”) if VSOE is not available, or best estimate of selling price (“BESP”) if neither VSOE nor TPE is available. We generally determine selling price based on amounts charged separately for the delivered and undelivered elements to similar customers in standalone sales of the specific elements. When arrangements include an EMA, we recognize revenue related to the EMA at the stated contractual price on a straight-line basis over the life of the agreement.
	We allocate our MEAs primarily among revenues for internally manufactured products, externally manufactured ancillary products, and service revenues. We use VSOE to allocate our internally manufactured products, estimated based on a historical analysis of our sales for these products outside of an MEA. We use TPE to allocate externally manufactured ancillary equipment, as these items are generally a pass through from a third party vendor to our end customers. Finally, we use best estimate of selling prices to allocate revenues to the services elements, as some of these services are not sold individually. We estimate the selling price based on a historical analysis of all service revenues sold individually outside of an MEA.
	Any taxes imposed by governmental authorities on our revenue-producing transactions with customers are shown in our consolidated statements of operations on a net-basis; that is, excluded from our reported revenues.
	Shipping and Handling Costs
	We classify shipping and handling costs related to product sales as cost of revenue, and any payments from customers for shipping and handling are categorized in revenue. We classify shipping and handling costs associated with receiving production inventory as cost of product revenue. Any materials received or shipped which are related to our engineering, sales, marketing and administrative functions are classified as operating expenses.
	Cash and Cash Equivalents
	Investments with a contractual maturity of three months or less when purchased are classified as cash equivalents.
	Fair Value of Financial Instruments
	Fair value is measured based on an exit price, representing the amount that would be received to sell an asset or paid to satisfy a liability in an orderly transaction between market participants. Fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, a fair value hierarchy is established, which categorizes the inputs used in measuring fair value as follows:
	Level 1—Quoted prices in active markets for identical assets or liabilities.
	Level 2—Significant observable inputs other than quoted prices in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data.
	Level 3—One or more significant inputs that are unobservable and supported by little or no market data.
	Inputs are referred to as assumptions that market participants would use in pricing the asset or liability. The uses of inputs in the valuation process are categorized into a three-level fair value hierarchy.
	Our financial instruments consist principally of cash and cash equivalents, accounts receivable, accounts payable and our revolving line of credit. We believe all of these financial instruments are recorded at amounts that approximate their current market values.
	Our Level 1 assets consist of cash equivalents, which are primarily invested in money-market funds. These assets are classified as Level 1 because they are valued using quoted prices in active markets and other relevant information generated by market transactions involving identical assets and liabilities.
	Our cash and cash equivalents include money-market funds for which the fair value was determined using Level 1 inputs and was $3.1 million as of December 31, 2013 and 2012. For cash and cash equivalents, accounts receivable, accounts payable and our revolving line of credit, the carrying amount approximates fair value because of the relative short maturity of those instruments.
	Allowance for Doubtful Accounts
	We estimate an allowance for doubtful accounts based on factors related to the credit risk of each customer. Historically, credit losses were minimal, primarily because the majority of our revenues were generated from large customers, primarily Caterpillar, Inc. (“Caterpillar”) and Hewlett Packard Corporation (“HP”). We perform credit evaluations of new customers and often require deposits, prepayments or use of bank instruments such as trade letters of credit or documentary collection to mitigate our credit risk. We write off uncollectable trade receivables, and record any recoveries of previous write offs against the allowance. Each reporting period we review our trade receivables for collectability and adjust the reserve adjust bad debt expense accordingly.  Our standard terms are net 30 days, however we may have agreements with certain distributors that allow for more extended terms.
	The following table summarizes the annual changes in our allowance for doubtful accounts (in thousands):
	Balance at December 31, 2010		$	330
	Change in provision charged to expense			9
	Write-off of uncollectible accounts			(2	)
	Balance at December 31, 2011		$	337
	Change in provision charged to expense			151
	Write-off of uncollectible accounts			-
	Balance at December 31, 2012		$	488
	Change in provision charged to expense			(139	)
	Write-off of uncollectible accounts			(36	)
	Balance at December 31, 2013		$	313
	Inventories
	Inventories are stated at the lower of cost or market, using the first-in-first-out method, and consisted of the following at December 31 (in thousands, net of allowances):
			2013			2012
	Raw materials		$	4,521		$	5,424
	Work in progress			2,429			2,186
	Finished goods			5,070			3,469
			$	12,020		$	11,079
	Property and Equipment
	Property and equipment is stated at cost and is depreciated using the straight-line method over the estimated useful lives of the assets, as follows (in years):
	Equipment			10-Feb
	Demonstration units			5-Mar
	Computers and purchased software			3-Feb
	Furnitures and fixtures			5-Feb
	Leasehold improvements are depreciated over the shorter of the life of the improvement or the remainder of the property lease term, including renewal options. Repairs and maintenance is expensed as incurred.
	Long-Lived Assets
Long-lived assets held and used by the Company are reviewed for impairment whenever events or changes in circumstances indicate that their net book value may not be recoverable. When such factors and circumstances exist, we compare the projected undiscounted future cash flows associated with the related asset or group of assets over their estimated useful lives against their respective carrying amounts. Impairment, if any, is based on the excess of the carrying amount over the fair value of those assets and is recorded in the period in which the determination was made. There was no impairment expense recognized for long-lived assets in 2013, 2012, or 2011.
Patent Application Costs
We have not capitalized patent application fees and related costs because of uncertainties regarding net realizable value of the technology represented by the existing patent applications and ultimate recoverability. All patent costs have been expensed through December 31, 2013.
Accrued Expenses
Accrued expenses consist of the following at December 31 (in thousands):
		2013			2012
Compensation, severance and benefits		$	2,685		$	2,351
Warranty liability			529			694
Taxes			483			320
Professional fees			759			502
Other			1,127			1,081
		$	5,583		$	4,948
Warranty Liability
Generally, the warranty period for our power quality products is 12 months from the date of commissioning or 18 months from the date of shipment from Active Power, whichever period is shorter. Occasionally we offer longer warranty periods to certain customers. The warranty period for products sold to our primary OEM customer, Caterpillar, is 12 months from the date of shipment to the end-user, or up to 36 months from shipment from Active Power. This is dependent upon Caterpillar complying with our storage requirements for our products in order to preserve this warranty period beyond the standard 18-month limit. We provide for the estimated cost of product warranties at the time revenue is recognized and this accrual is included in accrued expenses and long term liabilities on the accompanying consolidated balance sheet.
Changes in the Company’s warranty liability are as follows (in thousands):
Balance at December 31, 2010		$	734
Warranty expense			742
Warranty charges incurred			(863	)
Balance at December 31, 2011		$	613
Warranty expense			1,294
Warranty charges incurred			(1,152	)
Balance at December 31, 2012		$	755
Warranty expense			589
Warranty charges incurred			(782	)
Balance at December 31, 2013		$	562
Warranty liability included in accrued expenses		$	529
Long term warranty liability			33
Balance at December 31, 2013		$	562
Long-Term Liabilities
Long term liabilities consisted of the following at December 31 (in thousands):
		2013			2012
Deferred revenue		$	601		$	533
Technology licensing agreement			88			100
Warranty liability			33			61
Sublease deposits			19			19
		$	741		$	713
Stock-Based Compensation Expense
Total stock-based compensation expense relating to our equity plans in the twelve-month period ended December 31, 2013, 2012 and 2011 was $1.7 million, $1.4 million and $1.7 million, respectively. Our weighted average forfeiture rate was 18.9%, 17.0% and 15.3% for 2013, 2012 and 2011, respectively. Details of our stock-based compensation include the following (in thousands):
		2013			2012			2011
Stock-based compensation expense by caption:
Cost of product revenue		$	254		$	216		$	199
Cost of service and other revenue			116			70			79
Research and development			204			153			166
Selling and marketing			587			484			455
General and administrative			539			486			807
		$	1,700		$	1,409		$	1,706
Stock-based compensation expense by type of award:
Stock options		$	1,488		$	1,213		$	1,707
Restricted stock awards			212			196			(1	)
		$	1,700		$	1,409		$	1,706
We account for our stock-based compensation using Black Scholes option valuation model. Stock-based compensation cost is estimated at the grant date based on the fair-value of the award and is recognized as expense ratably over the requisite service period of the award. We develop our estimates of volatility, expected life, and forfeitures based on historical data and market information that can change significantly over time. We estimate stock price volatility based on implied and historical volatilities. Estimated option life and forfeiture rate assumptions are derived from historical data. The risk-free rates are based on the U.S. Treasury yield in effect at the time of grant.
Assumptions used in the Black-Scholes model for our stock plans are presented below:
		2013			2012			2011
Weighted average expected life in years		6.35 years			6.83 years			6.22 years
Weighted average expected volatility			76	%		77	%		76	%
Volatility Range			75%-76	%		75%-78	%		75%-76	%
Risk-free interest rate range			1.13%-2.38	%		0.63%-1.00	%		1.00%-2.25	%
Income Taxes
We account for income taxes using the liability method of accounting for income taxes. Under the liability method, deferred taxes are determined based on the differences between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. A valuation allowance is recorded to reduce the carrying amounts of deferred tax assets if it is more likely than not such assets will not be realized. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes.
We recognize the financial statement benefit of a tax position only after determining that the relevant tax authority would more likely than not sustain the position following an audit. For tax positions meeting the more likely-than-not threshold, the amount recognized in the financial statements is the largest benefit that has a greater than 50 percent likelihood of being realized upon the ultimate settlement with the relevant tax authority. A number of years may elapse before a particular matter, for which we have recorded a liability, is audited and effectively settled. We review our tax positions quarterly and adjust the balance as new information becomes available. We classify interest accrued related to unrecognized tax benefits as interest expense.
We recognize and measure benefits for uncertain tax positions based upon a number of factors, including changes in facts or circumstances, changes in tax law, correspondence with tax authorities during the course of audits and effective settlement of audit issues. At December 31, 2013 and 2012, the Company had no material unrecognized tax benefits.
The Company recognizes interest and penalties related to uncertain tax positions in income tax expense. As of December 31, 2013, the Company had no accrued interest or penalties related to uncertain tax positions.
Segment Reporting
Active Power’s chief operating decision maker allocates resources and assesses the performance of its power management product development and sales activities as one segment.
Concentration of Credit Risk
Financial instruments which potentially subject Active Power to concentrations of credit risk consist of cash and cash equivalents, investments and accounts receivable. Active Power’s cash and cash equivalents and investments are placed with high credit quality financial institutions and issuers. Active Power performs credit evaluations of its customers’ financial condition prior to entering into commercial transactions. We generally require letters of credit or prepayments from higher-risk customers as deemed necessary to ensure collection. Our allowance for doubtful accounts is estimated based on factors related to the credit risk of each customer. Individual receivables are written off after they have been deemed uncollectible. We also purchase several components from sole source or limited source suppliers.
Economic Dependence
We are significantly dependent on our relationships with Hewlett Packard Corporation (“Hewlett Packard”) and Caterpillar. If these relationships are unsuccessful or discontinue, our business and revenue may suffer. The loss of or a significant reduction in orders from Hewlett Packard or Caterpillar, or the failure to provide adequate service and support to the end-users of our products by Hewlett Packard or Caterpillar, could significantly reduce our revenue. Our operating results in the foreseeable future will continue to depend on the sales made by a relatively small number of customers, including Hewlett Packard and Caterpillar.
The following customers accounted for a significant percentage of Active Power’s total revenue during each of the years ended December 31:
		2013			2012			2011
Caterpillar			14	%		13	%		16	%
Hewlett Packard			22	%		35	%		36	%
European based IT Customer			-			12	%		-
No other customer represented more than 10% of our revenues in any of the years reported. Caterpillar represented 23% of our outstanding accounts receivable at December 31, 2013.  Hewlett Packard represented 23% of our outstanding receivables at December 31, 2012. In 2012, we had one additional customer from the EMEA region that represented more than 10% of our revenue.
Advertising Costs
We expense advertising costs as incurred. These expenses were approximately $23,000, $36,000 and $90,000 in 2013, 2012 and 2011, respectively.
Net (Loss) Per Share
The following table sets forth the computation of basic and diluted net loss per share (in thousands) for the years ended December 31:
		2013			2012			2011
Net loss		$	(8,351	)	$	(1,922	)	$	(7,094	)
Basic and diluted:
Weighted-average shares of common stock outstanding used in computing basic and diluted net loss per share			19,329			18,584			16,104
Basic and diluted net loss per share		$	(0.43	)	$	(0.10	)	$	(0.44	)
The calculation of diluted net loss per share excludes 2,407,664, 1,882,584 and 1,943,648 shares of common stock issuable upon exercise of employee stock options as of December 31, 2013, 2012 and 2011, respectively, and 53,038 and 200,071 non-vested shares of common stock issuable upon exercise of restricted stock awards as of December 31, 2013 and 2012, respectively, because their inclusion in the calculation would be anti-dilutive.
Recent Accounting Pronouncements
In February 2013, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2013-02, “Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income” (AOCI). ASU 2013-02 requires a roll-forward of changes in AOCI by component and information about significant reclassifications from AOCI to Net earnings to be presented in one location, either on the face of the financial statements or in the notes. This new guidance is effective for fiscal years beginning after December 15, 2012 and subsequent interim periods. The requirements of ASU 2013-02 did not have a material impact on our consolidated financial statements. The only reclassification from AOCI to net earnings in 2013 was in relation to the settlement of translation on a liquidated subsidiary which was less than $0.1 million and was reflected in other income (expense), net, in the consolidated statement of operations.
In March 2013, the FASB issued ASU 2013-05, “Parent's Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entity.” ASU 2013-05 clarifies the application of GAAP to the release of cumulative translation adjustments related to changes of ownership in or within foreign entities, including step acquisitions. This new guidance is effective for annual reporting periods beginning on or after December 15, 2013 and subsequent interim periods. We do not anticipate this pronouncement to have a material impact on our consolidated financial statements.
In July 2013, the FASB issued ASU 2013-11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carry-forward, a Similar Tax Loss, or a Tax Credit Carryforward Exists.” ASU 2013-11 clarifies guidance and eliminates diversity in practice on the presentation of unrecognized tax benefits when a net operating loss carry-forward, a similar tax loss, or a tax credit carry-forward exists at the reporting date. This new guidance is effective for annual reporting periods beginning on or after December 15, 2013 and subsequent interim periods. We are currently assessing the impact, if any, on our consolidated financial statements.

Property_and_Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2013
Property and Equipment [Abstract]	'
Property and Equipment	'
	2. Property and Equipment
	Property and equipment consists of the following at December 31 (in thousands):
		2013			2012
	Equipment	$	9,168		$	10,298
	Demonstration units		1,470			1,828
	Computers and purchased software		3,273			4,251
	Furnitures and fixtures		380			444
	Leasehold improvements		7,216			7,662
	Construction in progress		458			188
			21,965			24,671
	Accumulated depreciation		(18,909	)		(22,213	)
		$	3,056		$	2,458
	In 2013, we reclassified $0.9 million of inventory into equipment related to test units for our latest generation UPS product.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2013
Stockholders' Equity [Abstract]	'
Stockholders' Equity	'
	3. Stockholders’ Equity
	Preferred Stock
	At December 31, 2013 and 2012, Active Power had 2,000,000 shares of preferred stock authorized and no shares outstanding.
	Common Stock
	Common stock reserved for future issuance at December 31, 2013 consisted of 3,667,109 shares of common stock reserved under our 2010 Stock Incentive Plan, of which 2,470,083 shares were subject to outstanding options and restricted shares and 1,185,026 shares were available for future grants of awards.  In May 2012, our Board of Directors approved the addition of 1,700,000 shares of our common stock to be issued in accordance with our 2010 Equity Incentive Plan, and such addition was subsequently approved by our stockholders. Options are subject to terms and conditions as determined by the Compensation Committee of our Board of Directors.
	In March 2012, we sold approximately 2.9 million shares of common stock at a purchase price of $3.40 per share, for proceeds, net of fees and expenses, of approximately $9.6 million, in an offering made under a shelf registration statement that we filed with the Securities and Exchange Commission and that had been declared effective in December 2009. The proceeds from this offering will be used by us to help fund our working capital requirements and for general corporate purposes.
	In February 2010, we sold approximately 2.7 million shares of common stock at a purchase price of $3.75 per share, for proceeds, net of fees and expenses, of approximately $9.0 million, in a firm-commitment underwritten offering made under a shelf registration statement that we had filed with the Securities and Exchange Commission and that had been declared effective in December 2009. The proceeds from this offering were designed to strengthen our balance sheet and for general corporate purposes.
	Stock Option Plan
	Since its inception, we have authorized 5,682,296 shares of common stock for issuance under our 2000 and 2010 Stock Incentive Plans, however, we are only issuing new shares of common stock under our 2010 Stock Incentive Plan. We grant options under these plans that vest over periods of up to four years. The term of each option is no more than ten years from the date of grant. The total fair value of option shares vested in the year was $1.4 million, $1.7 million, and $0.9 million in 2013, 2012 and 2011, respectively.
	Our policy is to issue new shares when we are required to issue shares upon share option exercises.
	A summary of common stock option activity is as follows:
		Number of Shares			Weighted-Average Exercise Price		Weighted-Average Contractual Life (in years)
	Outstanding at December 31, 2012		1,882,584		$	6.67
	Granted		1,470,200			3.86
	Exercised		(200,025	)		3.56
	Canceled		(745,095	)		6.57
	Outstanding at December 31, 2013		2,407,664		$	5.27		6.47
	Vested and expected to vest at December 31, 2013		1,982,004		$	5.62		5.99
	Exercisable at December 31, 2013		1,070,423		$	6.89		4.01
	The weighted average grant date fair value per share of options granted during 2013, 2012 and 2011 was $2.60, $2.60 and $6.76, respectively.  The total intrinsic value of options exercised (which is the amount by which the stock price exceeded the exercise price of the options at the date of exercise) during the years ended December 31, 2013, 2012 and 2011 was $0.1 million, $0.1 million and $0.6 million, respectively. The aggregate intrinsic value of options outstanding and exercisable at December 31, 2013 was $0.4 million and $0.1 million, respectively.
	As of December 31, 2013, there was $2.4 million of total unrecognized compensation cost, related to non-vested stock options, that is expected to be recognized over a weighted-average vesting period of 3.1 years.
	Restricted (non-vested) Shares
	In 2013 and 2012, we issued approximately 6,000 and 248,000 restricted shares, respectively, to directors and employees of the Company. The restrictions lapse as the shares vest in equal quarterly installments over a four year period from the date of issuance. We recorded stock compensation expense related to restricted share units of $0.2 million in 2013. A summary of our restricted, or non-vested, shares is as follows:
		Number of Shares			Weighted-Average Grant Date Fair Value
	Outstanding at December 31, 2012		200,071		$	3.81
	Granted		6,000			4.01
	Vested		(82,248	)		3.81
	Canceled		(70,785	)		3.67
	Outstanding at December 31, 2013		53,038		$	4
	As of December 31, 2013, there was $0.2 million of total unrecognized compensation cost related to restricted shares that is expected to be recognized over a weighted-average vesting period of 2.1 years. The total fair value of restricted share units vested in 2013 and 2012 was $0.3 million and $1.0 million, respectively. There were no material grants of restricted share units in 2011.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Taxes [Abstract]	'
Income Taxes	'
	4. Income Taxes
	There has been no provision or benefit for income taxes attributable to continuing operations recorded in the consolidated statement of operations in 2013 or 2012.
	As of December 31, 2013, the Company had federal net operating loss carry-forwards of approximately $217.0 million and research and development credit carry-forwards of approximately $3.7 million. The net operating loss and credit carry-forwards will expire beginning in 2018, if not utilized. Utilization of the net operating losses and credit carry-forwards may be subject to a substantial annual limitation due to the “change of ownership” provisions of the Internal Revenue Code of 1986. The annual limitation may result in the expiration of net operating losses and credit carry-forwards before utilization.
	Significant components of the Company’s deferred taxes as of December 31 are as follows (in thousands):
		2013			2012
	Deferred tax assets:
	Current deferred tax assets
	Reserves and allowances	$	1,177		$	1,338
	Deferred Rent		55
	Deferred revenue		328			267
	Valuation allowance for current deferred tax assets		(1,558	)		(1,604	)
	Net current deferred tax assets	$	2		$	1
	Noncurrent deferred tax assets
	Acquired technology		695			791
	Capital expenses		1,624			1,850
	Stock compensation		699			706
	Net operating loss and tax credit carryforwards		84,356			78,191
	Valuation allowance for noncurrent deferred tax assets		(87,263	)		(81,433	)
	Net noncurrent deferred tax assets	$	111		$	105
	Deferred tax liabilities:
	Current deferred tax liabilities
	Prepaid expenses		(113	)		(106	)
	Total current deferred tax liabilities	$	(113	)	$	(106	)
	Net current deferred tax aset (liability)	$	(111	)	$	(105	)
	Net noncurrent deferred tax aset (liability)	$	111		$	105
	Net deferred taxes	$	-		$	-
	The Company has established a valuation allowance equal to the net deferred tax asset due to uncertainties regarding the realization of deferred tax assets based on the Company’s lack of earnings history. The valuation allowance decreased by approximately $5.8 million during 2013. Approximately $6.4 million of the total valuation allowance in 2013 relates to tax benefits for stock option deductions included in the net operating loss carry-forward, which when realized, will be allocated directly to additional paid in capital to the extent the benefits exceed amounts attributable to deferred compensation expense.
	The Company’s provision for income taxes differs from the expected tax benefit amount computed by applying the statutory federal income tax rate of 34% to income before taxes due to the following:
		Year Ended December 31,
		2013			2012			2011
	Federal statutory rate		(34.0	)%		(34.0	)%		(34.0	)%
	State taxes, net of federal benefit		(13.5	)		7.2			1.8
	R&D credits		(5.6	)		1.3			(1.2	)
	Stock compensation		6.2			14.5			10
	Effect of foreign operations		(20.5	)		157.3			2.5
	Expiration of net operating losses		-			63.2			-
	Permanent items and other		(1.9	)		6.8			0.1
	Change in valuation allowance		69.3			(216.3	)		21
			-	%		-	%		0.2	%
	The Company recognized no material adjustment in the liability for unrecognized income tax benefits. The reconciliation of the Company’s unrecognized tax benefits at the beginning and end of the year is as follows:
	Balance at January 1, 2013	$	1,677
	Additions based on tax positions related to the current year		290
	Additions for tax positions of prior years		23
	Balance at December 31, 2013	$	1,990
	Due to the existence of the valuation allowance, future changes in our unrecognized tax benefits will not materially impact the Company’s effective tax rate.
	The tax years 2009 through 2013 remain open to examination by the major taxing jurisdictions to which the Company is subject.

Commitments

Commitments	12 Months Ended
	Dec. 31, 2013
Commitments [Abstract]	'
Commitments	'
	5. Commitments
	We lease our office and manufacturing and engineering facilities and our foreign sales offices under operating lease agreements. These facilities’ leases are non-cancelable and obligate us to pay taxes and maintenance costs. Our corporate headquarters facility is subject to a lease agreement that expires in December 2016. From 2007 to December 2011, we subleased 31,000 square feet of our corporate headquarters facility pursuant to sublease agreements. Rent expense was offset by $0.3 million in 2011 for cash received pursuant to these sublease agreements. Our engineering facility of approximately 12,000 square feet is leased pursuant to a lease agreement that expires in March 2016. In July 2011, we leased an additional 26,195 square feet in a facility adjacent to our headquarters facility, in order to expand our manufacturing facility. This lease expired and we vacated the space in January 2013. For leases with escalating or de-escalating rent payments, we straight-line the cash flows over the period of the lease and defer the differences between cash flows and expense in the income statement on the balance sheet in either accrued expenses or prepaids and other assets. Net deferred rent on the consolidated balance sheet as of December 31, 2013 was $0.1 million. There was no deferred rent in 2012 or 2011.
	In addition, we lease certain equipment such as copiers and phone systems under non-cancelable leases. Net rent expense was $1.7 million, $1.7 million and $1.3 million for the years ended December 31, 2013, 2012 and 2011, respectively.
	Future minimum payments under these leases at December 31, 2013 are as follows (in thousands):
		Rental payments
	2014	$	1,228
	2015		1,193
	2016		1,068
	2017		113
	2018		72
	Total future minimum lease payments	$	3,674
	We enter into certain commitments to purchase inventory and other items in the course of normal operations. At December 31, 2013, the total of these commitments was $3.3 million, of which $3.2 million will mature in 2014 and $25,000 will mature in each subsequent year through 2017.
	We have entered into Severance Benefits Agreements with our Chief Executive Officer (“CEO”) and Chief Financial Officer (“CFO”) and with each of our other executive officers. These agreements generally provide that, if within 12 months following a change in control the executive officer’s employment is terminated for reasons other than for cause (as defined in the agreement) or by the executive for good reason, including a significant reduction in the role and/or responsibility of the executive within 12 months of the change in corporate control, then all outstanding stock options or restricted shares held by the executive would vest as of the date of the termination and certain severance payments would be payable. In the case of our CEO and CFO, in the event of termination by the Company for reasons other than for cause or by him for good reason, he would be entitled to a severance payment equal to 12 months of salary and be entitled to receive health benefits for 12 additional months after termination. In the case of our other executive officers, in the event of a termination by the Company for reasons other than for cause or by the officer for good reason, they would be entitled to a severance payment equivalent to six months of salary and be entitled to receive health benefits for six additional months after termination.

Employee_Benefit_Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2013
Employee Benefit Plan [Abstract]	'
Employee Benefit Plan	'
	6. Employee Benefit Plan
	We maintain a 401(k) Plan that covers substantially all full-time employees. Company contributions to the plan are determined at the discretion of the Board of Directors and vest ratably over five years of service starting after the first year of employment. We did not contribute to this plan in 2013, 2012 or 2011.

Geographic_Information

Geographic Information	12 Months Ended
	Dec. 31, 2013
Geographic Information [Abstract]	'
Geographic Information	'
	7. Geographic Information
	Revenues for the year ended December 31 were as follows (in thousands):
		2013		2012
	Americas	$	50,365	$	48,190
	Europe, Middle East and Africa		6,941		21,917
	Asia		4,393		6,208
	Total	$	61,699	$	76,315
	Revenues from foreign countries above represented shipments to customers located in 34 countries during 2013. We often ship to areas that are outside of the jurisdiction in which revenue is recognized. Substantially all of our property, plant and equipment are located in the United States. Net assets of operations in foreign countries (excluding intercompany receivables and payables eliminated in consolidation) were $5.8 million at December 31, 2013 and were mostly located in the UK, Germany and China.

Guarantees

Guarantees	12 Months Ended
	Dec. 31, 2013
Guarantees [Abstract]	'
Guarantees	'
	8. Guarantees
	In certain geographical regions, particularly Europe, we are sometimes required to issue performance guarantees to our customers as a condition of sale. These guarantees usually provide financial protection to our customers in the event that we fail to fulfill our delivery or warranty obligations. We secure these guarantees with standby letters of credit through our bank. At December 31, 2013 and 2012 we had $0.5 million and $0, respectively, of performance guarantees outstanding to customers that were secured with letters of credit.  The current guarantee is set to expire on April 17, 2014. There is no foreseeable risk that we will not be able to meet the performance obligations. Our restricted cash, as shown on the balance sheet, is related to these guarantees.

Revolving_Credit_Facility

Revolving Credit Facility	12 Months Ended
	Dec. 31, 2013
Revolving Credit Facility [Abstract]	'
Revolving Credit Facility	'
	9. Revolving Credit Facility
	In August 2010, we entered into a Second Amended and Restated Loan and Security Agreement (the “Loan Agreement”) with Silicon Valley Bank (“SVB”). This facility increased the total liquidity available from $6.0 million to $12.5 million subject to certain borrowing bases. This new facility expanded our ability to borrow funds from United States receivables to also include qualifying receivables from our United Kingdom operations, as well, increased our ability to use inventory as collateral, and also added an ability to borrow against purchase orders. These additional bases of borrowing were designed to allow us to use the credit facility to fund inventory purchases in the event we received large or multiple sales orders that would require a major investment in inventory and work in progress, to help fund continued growth in our business, and to manage our working capital requirements.
	This loan facility provides for a secured revolving line of credit in an aggregate amount of up to eighty percent (80%) of the facility amount of $15.625 million, or $12.5 million, subject to certain borrowing bases. In the event we have maintained cash and cash equivalents of at least $6.25 million with SVB for at least 30 consecutive days, which is referred to as being in a “Streamline Period”, the borrowing base formula is based on eligible accounts receivable, eligible purchase orders and eligible inventory, subject to a sublimit of $5.0 million for U.K. accounts receivable, $3.5 million for inventory and $1.5 million for purchase orders. When we are not in a Streamline Period, our borrowings are limited based on accounts receivable and purchase orders that SVB has specifically agreed to finance and a borrowing base for eligible inventory. We may also request that SVB issue letters of credit on our behalf, of up to $1.5 million, as a portion of our total loan facility.
	On August 5, 2010, we borrowed approximately $2.5 million in revolving loans, all of which was used to refinance all indebtedness owing from us to SVB under our previous credit facility. The new credit facility increased the total credit available from our previous loan facility with SVB, which was $5.0 million, and enables us to borrow against eligible inventory, foreign receivables and customer purchase orders in addition to eligible accounts receivable.
	In August 2012, we entered into the Second Amendment to Second Amended and Restated Loan and Security Agreement with SVB (the “Amendment”) which amends the Second Amended and Restated Loan and Security Agreement, dated as of August 5, 2010, by and between us and SVB. Pursuant to the Amendment, the maturity date of the loan facility was extended by two years, to August 5, 2014, unless earlier terminated by us, subject to any then applicable early termination fee. The Amendment further provides for, among other things, (i) adding a $1.5 million sublimit under the borrowing base formula for 91 to 120 day aged accounts receivable, (ii) removing eligible purchase orders from the borrowing base formula, and (iii) removing sublimits providing for the issuance of letters of credit and cash management services. Additionally, pursuant to the Amendment, the definition of “Streamline Period” was amended such that the Company will be deemed to be in a Streamline Period in the event that it has a liquidity ratio of greater than or equal to 1.75:1.00 at all times for at least 60 consecutive days; provided that a Streamline Period will automatically be in effect if the Company achieves such liquidity ratio as a result of the sale of its equity securities.
	Further, the Amendment provides for, among other things, (i) amending the finance charge on each eligible account financed by SVB to a per annum rate equal to SVB’s prime rate, subject to a minimum prime rate of four percent (4.00%), plus (a) one and one-quarter percent (1.25%) when we are in a Streamline Period or (b) one and three-quarters percent (1.75%) for eligible accounts (other than eligible 91 to 120 day aged accounts) and (c) two percent (2.00%) for eligible 91 to 120 day aged accounts when we are not in a Streamline Period, and (ii) reducing the interest rate upon which each inventory advance accrues interest such that each advance based upon inventory accrues interest at a per annum rate equal to SVB’s prime rate, subject to a minimum prime rate of four percent (4.00%), plus (a) one and one-quarter percent (1.25%) when we are in a Streamline Period or (b) three and one half percent (3.50%) when the Company is not in a Streamline Period.
	Finance charges and interest are payable monthly, and all principal is due on the maturity date of August 5, 2014. However, when we are not in a Streamline Period, we must repay advances based on receivables when we receive payment on the receivable that has been financed, and we must repay advances based on purchase orders within 120 days of the date of the purchase order, together with all finance charges on such advances.
	The revolving loans made to us under this loan facility are secured by a lien on substantially all of our assets. In addition, on August 5, 2010, Active Power Solutions Limited, a wholly-owned United Kingdom subsidiary of the Company, entered into a Guarantee and Debenture with SVB (the “Guarantee and Debenture”), pursuant to which Active Power Solutions Limited guarantied all of the obligations of the Company under the Loan Agreement and secured its obligations under the Guarantee and Debenture with a security interest on substantially all of its assets.
	The Loan Agreement includes customary affirmative covenants for a credit facility of this size and type, including delivery of financial statements, compliance with laws, maintenance of insurance, and protection of intellectual property rights. Further, the Loan Agreement contains customary negative covenants for a credit facility of this size and type, including covenants that limit or restrict our ability to, among other things, dispose of assets, change our business, change our CEO or CFO without replacing such person within 120 days, have a change in control, make acquisitions, be acquired, incur indebtedness, grant liens, make investments, make distributions, repurchase stock, and enter into certain transactions with affiliates. The Loan Agreement also requires the Company to maintain a minimum liquidity ratio of 1.25:1. The liquidity ratio is defined as the ratio of unrestricted cash and cash equivalents and marketable securities plus eligible accounts receivable to all indebtedness owed by the Company to SVB. The Company is currently in compliance with all loan covenants under the Loan Agreement.
	The Loan Agreement contains customary events of default that include, among other things, non-payment defaults, covenant defaults, material adverse change defaults, insolvency defaults, material judgment defaults and inaccuracy of representations and warranty defaults. The occurrence of an event of default could result in the acceleration of obligations under the Loan Agreement, in which case the Company must repay all loans and related charges, fees and amounts then due and payable, and our subsidiary may be required to pay any such amounts under the Guarantee and Debenture. At the election of SVB, upon the occurrence and during the continuance of an event of default, finance charges or interest rates, as applicable, will increase an additional five percentage points (5.00%) per annum above the rate that is otherwise applicable thereto upon the occurrence of such event of default, and the collateral handling fees will increase by one-half percent (0.50%).
	At December 31, 2013 and 2012, $5.5 million was outstanding on these borrowings, at an interest rate of 5.25%. Based on the borrowing base formula, we had an additional $3.9 million available for use at December 31, 2013 under this credit facility.

Selected_Quarterly_Consolidate

Selected Quarterly Consolidated Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2013
Selected Quarterly Consolidated Financial Data (unaudited) [Abstract]	'
Selected Quarterly Consolidated Financial Data (unaudited)	'
	10. Selected Quarterly Consolidated Financial Data (unaudited)
	The following tables present selected unaudited consolidated statement of operations information for each of the quarters in the years ended December 31, 2013 and 2012 (in thousands, except per share data):
		For the Quarter Ended
	Year Ended December 31, 2013	31-Dec			30-Sep			30-Jun		31-Mar
	Selected consolidated statement of operations information:
	Total revenue	$	13,926		$	13,154		$	20,195	$	14,424
	Total cost of goods sold	$	9,750		$	9,210		$	13,273	$	10,070
	Gross profit	$	4,176		$	3,944		$	6,922	$	4,354
	Operating expenses	$	7,990		$	6,909		$	6,412	$	5,702
	Operating profit (loss)	$	(3,814	)	$	(2,965	)	$	510	$	(1,348	)
	Net income (loss)	$	(4,127	)	$	(3,135	)	$	332	$	(1,421	)
	Basic and diluted new income (loss) per share	$	(0.21	)	$	(0.16	)	$	0.02	$	(0.07	)
	Selected consolidated balance sheet information:
	Current assets	$	34,556		$	39,110		$	45,722	$	42,019
	Total assets	$	37,907		$	42,263		$	49,052	$	44,748
	Current liabilities	$	16,860		$	18,194		$	22,758	$	19,208
	Working capital	$	17,696		$	20,916		$	22,964	$	22,811
	Long term obligations	$	741		$	737		$	689	$	774
	Stockholders' equity	$	20,306		$	23,332		$	25,605	$	24,766
		For the Quarter Ended
	Year Ended December 31, 2012	31-Dec			30-Sep			30-Jun		31-Mar
	Selected consolidated statement of operations information:
	Total revenue	$	15,247		$	19,611		$	21,659	$	19,798
	Total cost of goods sold	$	9,227		$	13,996		$	13,887	$	14,491
	Gross profit	$	6,020		$	5,615		$	7,772	$	5,307
	Operating expenses	$	6,329		$	6,463		$	7,269	$	6,379
	Operating profit (loss)	$	(309	)	$	(848	)	$	503	$	(1,072	)
	Net income (loss)	$	(418	)	$	(847	)	$	490	$	(1,147	)
	Basic and diluted new income (loss) per share	$	(0.02	)	$	(0.04	)	$	0.03	$	(0.06	)
	Selected consolidated balance sheet information:
	Current assets	$	43,032		$	42,950		$	44,334	$	44,352
	Total assets	$	45,799		$	46,135		$	47,787	$	47,892
	Current liabilities	$	19,087		$	19,501		$	20,812	$	21,551
	Working capital	$	23,945		$	23,449		$	23,522	$	22,801
	Long term obligations	$	713		$	798		$	834	$	748
	Stockholders' equity	$	25,999		$	18,900		$	19,937	$	20,519

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
	11. Subsequent Events
	On February 26, 2014, we entered into an underwriting agreement to sell 3,651,250 shares of our common stock at $3.15 per share in a public offering (including shares subject to the underwriter’s over-allotment option). The aggregate net proceeds to us were approximately $10.4 million, after deducting $1.0 million in offering related expenses and underwriting discounts and commissions. The transaction closed on March 3, 2014.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Summary of Significant Accounting Policies [Abstract]	'
Description of Business	'
	Description of Business
	Active Power, Inc. and its subsidiaries (hereinafter referred to as “we”, “us”, “Active Power” or the “Company”) design, manufacture and sell our flywheel-based uninterruptible power supply (“UPS”) products and modular infrastructure solutions (“MIS”) which are designed to ensure continuity for data centers and other mission critical operations in the event of power disturbances. Our products and solutions are designed to deliver continuous conditioned (“clean”) power during power disturbances and outages, voltage surges and sags, and provide ride-through power in the event of a utility failure, supporting operations until utility power is restored or a longer term alternative power source, such as a diesel generator, is started. We sell our products globally through our direct sales force, manufacturer’s representatives, Original Equipment Manufacturer (“OEM”) channels and IT partners. Our current principal markets are the Americas, Europe Middle East and Africa (“EMEA”), and Asia.
	We were founded as a Texas Corporation in 1992 and reincorporated in Delaware in 2000 prior to our initial public offering. Our headquarters are in Austin, Texas with international offices in the UK, Germany and China.
	The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“US GAAP”) and include the accounts of the Company and its consolidated subsidiaries. All intercompany transactions and balances have been eliminated upon consolidation.
	The accompanying consolidated financial statements have also been prepared on the assumption that the Company will continue to operate as a going concern. Accordingly assets and liabilities are recorded on the basis that the Company will be able to realize its assets and discharge its liabilities in the normal course of business. The Company’s history of operating losses and use of cash, in the absence of other factors, may cause uncertainty as to its ability to continue as a going concern. We have reviewed the current and prospective sources of liquidity, significant conditions and events and forecast financial results and concluded that we have adequate resources to continue to operate as a going concern. Our business plan and our assumptions around the adequacy of our liquidity are based on estimates regarding expected revenues and future costs. However, our revenues may not meet our projections or our costs may exceed our estimates. Further, our estimates may change and future events or developments may also affect our estimates. Any of these factors may change our expectation of cash usage in 2014 or significantly affect our level of liquidity, which may require us to seek additional financing or take other measures to reduce our operating costs in order to continue operating. These financial statements do not include any adjustments that might result from the Company not being able to continue as a going concern.
	All common stock information and related share prices included in these notes to financial statements have been adjusted to reflect the five for one reverse stock split that occurred on December 21, 2012.
	As previously disclosed in its September 5, 2013 press release and Form 8-K, the Company announced in error in April 2013 that it had entered into a strategic distribution agreement in China with Digital China Information Service Company Limited (“Digital China”). The actual party to this agreement is Qiyuan Network System Limited (“Qiyuan”). A Company employee in China represented to management that Qiyuan was a subsidiary of Digital China. Management subsequently discovered that the Company employee in China intentionally misrepresented the relationship between Qiyuan and Digital China. Qiyuan has no affiliation with Digital China. Due to this discovery, we restated our first quarter 2013 and second quarter 2013 results on Form 10-Q/A.
Use of Estimates	'
	Use of Estimates
	The preparation of financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. Changes in the estimates or assumptions used by management could have a material impact upon reported amounts and our results of operations.
Revenue Recognition	'
	Revenue Recognition
	In general, we recognize revenue when four criteria are met: (i) persuasive evidence that an arrangement exists; (ii) delivery has occurred or services have been rendered; (iii) the sales price is fixed or determinable; and (iv) collectability is reasonably assured. In general, revenue is recognized when revenue-generating transactions generally fall into one of the following categories of revenue recognition:
		●	We recognize product revenue at the time of shipment for a significant portion of all products sold directly to customers and through distributors because title and risk of loss pass on delivery to the common carrier. Our customers and distributors do not have the right to return products. If title and risk of loss pass at some other point in time, we recognize such revenue for our customers when the product is delivered to the customer and title and risk of loss has passed. We may enter into bill-and-hold arrangements and when this happens delivery may not be occur, but other criteria are reviewed to determine proper timing of revenue recognition.
		●	We recognize installation, service and maintenance revenue at the time the service is performed.
		●	We recognize revenue associated with extended maintenance agreements (“EMAs”) over the life of the contracts using the straight-line method, which approximates the expected timing in which applicable services are performed. Amounts collected in advance of revenue recognition are recorded as a current liability in the deferred revenue line of the consolidated balance sheet or long-term liability based on the time from the balance sheet date to the future date of revenue recognition.
		●	We recognize revenue on certain rental programs over the life of the rental agreement using the straight-line method. Amounts collected in advance of revenue recognition are recorded as a current or long-term liability based on the time from the balance sheet date to the future date of revenue recognition.
		●	Shipping costs reimbursed by the customer are included in revenue.
	When collectability is not reasonably assured, we defer revenue and will recognize revenue on a cost recovery basis as payments are received.
	Multiple element arrangements (“MEAs”) are arrangements to sell products to customers frequently include multiple deliverables. Our most significant MEAs include the sale of one or more of our CleanSource UPS or CleanSource PowerHouse products, combined with one or more of the following products: design services, project management, commissioning and installation services, spare parts or consumables, and EMA’s. Delivery of the various products or performance of services within the arrangement may or may not coincide. Certain services related to design and consulting may occur prior to delivery of product and commissioning and installation typically take place within six months of product delivery, depending upon customer requirements. EMAs, consumables, and repair, maintenance or consulting services generally are delivered over a period of one to five years. In certain arrangements revenue recognized is limited to the amount invoiced or received that is not contingent on the delivery of future products and services.
	When arrangements include multiple elements, we allocate revenue to each element based on the relative selling price and recognize revenue when the elements have standalone value and the four criteria for revenue recognition have been met. We establish the selling price of each element based on Vendor Specific Objective Evidence (“VSOE”) if available, Third Party Evidence (“TPE”) if VSOE is not available, or best estimate of selling price (“BESP”) if neither VSOE nor TPE is available. We generally determine selling price based on amounts charged separately for the delivered and undelivered elements to similar customers in standalone sales of the specific elements. When arrangements include an EMA, we recognize revenue related to the EMA at the stated contractual price on a straight-line basis over the life of the agreement.
	We allocate our MEAs primarily among revenues for internally manufactured products, externally manufactured ancillary products, and service revenues. We use VSOE to allocate our internally manufactured products, estimated based on a historical analysis of our sales for these products outside of an MEA. We use TPE to allocate externally manufactured ancillary equipment, as these items are generally a pass through from a third party vendor to our end customers. Finally, we use best estimate of selling prices to allocate revenues to the services elements, as some of these services are not sold individually. We estimate the selling price based on a historical analysis of all service revenues sold individually outside of an MEA.
	Any taxes imposed by governmental authorities on our revenue-producing transactions with customers are shown in our consolidated statements of operations on a net-basis; that is, excluded from our reported revenues.
Shipping and Handling Costs	'
	Shipping and Handling Costs
	We classify shipping and handling costs related to product sales as cost of revenue, and any payments from customers for shipping and handling are categorized in revenue. We classify shipping and handling costs associated with receiving production inventory as cost of product revenue. Any materials received or shipped which are related to our engineering, sales, marketing and administrative functions are classified as operating expenses.
Cash Equivalents	'
	Cash and Cash Equivalents
	Investments with a contractual maturity of three months or less when purchased are classified as cash equivalents.
Fair Value of Financial Instruments	'
	Fair Value of Financial Instruments
	Fair value is measured based on an exit price, representing the amount that would be received to sell an asset or paid to satisfy a liability in an orderly transaction between market participants. Fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, a fair value hierarchy is established, which categorizes the inputs used in measuring fair value as follows:
	Level 1—Quoted prices in active markets for identical assets or liabilities.
	Level 2—Significant observable inputs other than quoted prices in Level 1, such as quoted prices for similar assets and liabilities in active markets; quoted prices for identical or similar assets and liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data.
	Level 3—One or more significant inputs that are unobservable and supported by little or no market data.
	Inputs are referred to as assumptions that market participants would use in pricing the asset or liability. The uses of inputs in the valuation process are categorized into a three-level fair value hierarchy.
	Our financial instruments consist principally of cash and cash equivalents, accounts receivable, accounts payable and our revolving line of credit. We believe all of these financial instruments are recorded at amounts that approximate their current market values.
	Our Level 1 assets consist of cash equivalents, which are primarily invested in money-market funds. These assets are classified as Level 1 because they are valued using quoted prices in active markets and other relevant information generated by market transactions involving identical assets and liabilities.
	Our cash and cash equivalents include money-market funds for which the fair value was determined using Level 1 inputs and was $3.1 million as of December 31, 2013 and 2012. For cash and cash equivalents, accounts receivable, accounts payable and our revolving line of credit, the carrying amount approximates fair value because of the relative short maturity of those instruments.
Allowance for Doubtful Accounts	'
	Allowance for Doubtful Accounts
	We estimate an allowance for doubtful accounts based on factors related to the credit risk of each customer. Historically, credit losses were minimal, primarily because the majority of our revenues were generated from large customers, primarily Caterpillar, Inc. (“Caterpillar”) and Hewlett Packard Corporation (“HP”). We perform credit evaluations of new customers and often require deposits, prepayments or use of bank instruments such as trade letters of credit or documentary collection to mitigate our credit risk. We write off uncollectable trade receivables, and record any recoveries of previous write offs against the allowance. Each reporting period we review our trade receivables for collectability and adjust the reserve adjust bad debt expense accordingly.  Our standard terms are net 30 days, however we may have agreements with certain distributors that allow for more extended terms.
	The following table summarizes the annual changes in our allowance for doubtful accounts (in thousands):
	Balance at December 31, 2010		$	330
	Change in provision charged to expense			9
	Write-off of uncollectible accounts			(2	)
	Balance at December 31, 2011		$	337
	Change in provision charged to expense			151
	Write-off of uncollectible accounts			-
	Balance at December 31, 2012		$	488
	Change in provision charged to expense			(139	)
	Write-off of uncollectible accounts			(36	)
	Balance at December 31, 2013		$	313
Inventories	'
	Inventories
	Inventories are stated at the lower of cost or market, using the first-in-first-out method, and consisted of the following at December 31 (in thousands, net of allowances):
			2013			2012
	Raw materials		$	4,521		$	5,424
	Work in progress			2,429			2,186
	Finished goods			5,070			3,469
			$	12,020		$	11,079
Property and Equipment	'
	Property and Equipment
	Property and equipment is stated at cost and is depreciated using the straight-line method over the estimated useful lives of the assets, as follows (in years):
	Equipment			10-Feb
	Demonstration units			5-Mar
	Computers and purchased software			3-Feb
	Furnitures and fixtures			5-Feb
	Leasehold improvements are depreciated over the shorter of the life of the improvement or the remainder of the property lease term, including renewal options. Repairs and maintenance is expensed as incurred.
Long-Lived Assets	'
	Long-Lived Assets
	Long-lived assets held and used by the Company are reviewed for impairment whenever events or changes in circumstances indicate that their net book value may not be recoverable. When such factors and circumstances exist, we compare the projected undiscounted future cash flows associated with the related asset or group of assets over their estimated useful lives against their respective carrying amounts. Impairment, if any, is based on the excess of the carrying amount over the fair value of those assets and is recorded in the period in which the determination was made. There was no impairment expense recognized for long-lived assets in 2013, 2012, or 2011.
Patent Application Costs	'
	Patent Application Costs
	We have not capitalized patent application fees and related costs because of uncertainties regarding net realizable value of the technology represented by the existing patent applications and ultimate recoverability. All patent costs have been expensed through December 31, 2013.
Accrued Expenses	'
	Accrued Expenses
	Accrued expenses consist of the following at December 31 (in thousands):
			2013			2012
	Compensation, severance and benefits		$	2,685		$	2,351
	Warranty liability			529			694
	Taxes			483			320
	Professional fees			759			502
	Other			1,127			1,081
			$	5,583		$	4,948
Warranty Liability	'
	Warranty Liability
	Generally, the warranty period for our power quality products is 12 months from the date of commissioning or 18 months from the date of shipment from Active Power, whichever period is shorter. Occasionally we offer longer warranty periods to certain customers. The warranty period for products sold to our primary OEM customer, Caterpillar, is 12 months from the date of shipment to the end-user, or up to 36 months from shipment from Active Power. This is dependent upon Caterpillar complying with our storage requirements for our products in order to preserve this warranty period beyond the standard 18-month limit. We provide for the estimated cost of product warranties at the time revenue is recognized and this accrual is included in accrued expenses and long term liabilities on the accompanying consolidated balance sheet.
	Changes in the Company’s warranty liability are as follows (in thousands):
	Balance at December 31, 2010		$	734
	Warranty expense			742
	Warranty charges incurred			(863	)
	Balance at December 31, 2011		$	613
	Warranty expense			1,294
	Warranty charges incurred			(1,152	)
	Balance at December 31, 2012		$	755
	Warranty expense			589
	Warranty charges incurred			(782	)
	Balance at December 31, 2013		$	562
	Warranty liability included in accrued expenses		$	529
	Long term warranty liability			33
	Balance at December 31, 2013		$	562
Long-Term Liabilities	'
	Long-Term Liabilities
	Long term liabilities consisted of the following at December 31 (in thousands):
			2013			2012
	Deferred revenue		$	601		$	533
	Technology licensing agreement			88			100
	Warranty liability			33			61
	Sublease deposits			19			19
			$	741		$	713
Stock-Based Compensation Expense	'
	Stock-Based Compensation Expense
	Total stock-based compensation expense relating to our equity plans in the twelve-month period ended December 31, 2013, 2012 and 2011 was $1.7 million, $1.4 million and $1.7 million, respectively. Our weighted average forfeiture rate was 18.9%, 17.0% and 15.3% for 2013, 2012 and 2011, respectively. Details of our stock-based compensation include the following (in thousands):
			2013			2012			2011
	Stock-based compensation expense by caption:
	Cost of product revenue		$	254		$	216		$	199
	Cost of service and other revenue			116			70			79
	Research and development			204			153			166
	Selling and marketing			587			484			455
	General and administrative			539			486			807
			$	1,700		$	1,409		$	1,706
	Stock-based compensation expense by type of award:
	Stock options		$	1,488		$	1,213		$	1,707
	Restricted stock awards			212			196			(1	)
			$	1,700		$	1,409		$	1,706
	We account for our stock-based compensation using Black Scholes option valuation model. Stock-based compensation cost is estimated at the grant date based on the fair-value of the award and is recognized as expense ratably over the requisite service period of the award. We develop our estimates of volatility, expected life, and forfeitures based on historical data and market information that can change significantly over time. We estimate stock price volatility based on implied and historical volatilities. Estimated option life and forfeiture rate assumptions are derived from historical data. The risk-free rates are based on the U.S. Treasury yield in effect at the time of grant.
	Assumptions used in the Black-Scholes model for our stock plans are presented below:
			2013			2012			2011
	Weighted average expected life in years		6.35 years			6.83 years			6.22 years
	Weighted average expected volatility			76	%		77	%		76	%
	Volatility Range			75%-76	%		75%-78	%		75%-76	%
	Risk-free interest rate range			1.13%-2.38	%		0.63%-1.00	%		1.00%-2.25	%
Income Taxes	'
	Income Taxes
	We account for income taxes using the liability method of accounting for income taxes. Under the liability method, deferred taxes are determined based on the differences between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect in the years in which the differences are expected to reverse. A valuation allowance is recorded to reduce the carrying amounts of deferred tax assets if it is more likely than not such assets will not be realized. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes.
	We recognize the financial statement benefit of a tax position only after determining that the relevant tax authority would more likely than not sustain the position following an audit. For tax positions meeting the more likely-than-not threshold, the amount recognized in the financial statements is the largest benefit that has a greater than 50 percent likelihood of being realized upon the ultimate settlement with the relevant tax authority. A number of years may elapse before a particular matter, for which we have recorded a liability, is audited and effectively settled. We review our tax positions quarterly and adjust the balance as new information becomes available. We classify interest accrued related to unrecognized tax benefits as interest expense.
	We recognize and measure benefits for uncertain tax positions based upon a number of factors, including changes in facts or circumstances, changes in tax law, correspondence with tax authorities during the course of audits and effective settlement of audit issues. At December 31, 2013 and 2012, the Company had no material unrecognized tax benefits.
	The Company recognizes interest and penalties related to uncertain tax positions in income tax expense. As of December 31, 2013, the Company had no accrued interest or penalties related to uncertain tax positions.
Segment Reporting	'
	Segment Reporting
	Active Power’s chief operating decision maker allocates resources and assesses the performance of its power management product development and sales activities as one segment.
Concentration of Credit Risk	'
	Concentration of Credit Risk
	Financial instruments which potentially subject Active Power to concentrations of credit risk consist of cash and cash equivalents, investments and accounts receivable. Active Power’s cash and cash equivalents and investments are placed with high credit quality financial institutions and issuers. Active Power performs credit evaluations of its customers’ financial condition prior to entering into commercial transactions. We generally require letters of credit or prepayments from higher-risk customers as deemed necessary to ensure collection. Our allowance for doubtful accounts is estimated based on factors related to the credit risk of each customer. Individual receivables are written off after they have been deemed uncollectible. We also purchase several components from sole source or limited source suppliers.
Economic Dependence	'
	Economic Dependence
	We are significantly dependent on our relationships with Hewlett Packard Corporation (“Hewlett Packard”) and Caterpillar. If these relationships are unsuccessful or discontinue, our business and revenue may suffer. The loss of or a significant reduction in orders from Hewlett Packard or Caterpillar, or the failure to provide adequate service and support to the end-users of our products by Hewlett Packard or Caterpillar, could significantly reduce our revenue. Our operating results in the foreseeable future will continue to depend on the sales made by a relatively small number of customers, including Hewlett Packard and Caterpillar.
	The following customers accounted for a significant percentage of Active Power’s total revenue during each of the years ended December 31:
			2013			2012			2011
	Caterpillar			14	%		13	%		16	%
	Hewlett Packard			22	%		35	%		36	%
	European based IT Customer			-			12	%		-
	No other customer represented more than 10% of our revenues in any of the years reported. Caterpillar represented 23% of our outstanding accounts receivable at December 31, 2013.  Hewlett Packard represented 23% of our outstanding receivables at December 31, 2012. In 2012, we had one additional customer from the EMEA region that represented more than 10% of our revenue.
Advertising Costs	'
	Advertising Costs
	We expense advertising costs as incurred. These expenses were approximately $23,000, $36,000 and $90,000 in 2013, 2012 and 2011, respectively.
Net Income (Loss) Per Share	'
	Net (Loss) Per Share
	The following table sets forth the computation of basic and diluted net loss per share (in thousands) for the years ended December 31:
			2013			2012			2011
	Net loss		$	(8,351	)	$	(1,922	)	$	(7,094	)
	Basic and diluted:
	Weighted-average shares of common stock outstanding used in computing basic and diluted net loss per share			19,329			18,584			16,104
	Basic and diluted net loss per share		$	(0.43	)	$	(0.10	)	$	(0.44	)
	The calculation of diluted net loss per share excludes 2,407,664, 1,882,584 and 1,943,648 shares of common stock issuable upon exercise of employee stock options as of December 31, 2013, 2012 and 2011, respectively, and 53,038 and 200,071 non-vested shares of common stock issuable upon exercise of restricted stock awards as of December 31, 2013 and 2012, respectively, because their inclusion in the calculation would be anti-dilutive.
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	In February 2013, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2013-02, “Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income” (AOCI). ASU 2013-02 requires a roll-forward of changes in AOCI by component and information about significant reclassifications from AOCI to Net earnings to be presented in one location, either on the face of the financial statements or in the notes. This new guidance is effective for fiscal years beginning after December 15, 2012 and subsequent interim periods. The requirements of ASU 2013-02 did not have a material impact on our consolidated financial statements. The only reclassification from AOCI to net earnings in 2013 was in relation to the settlement of translation on a liquidated subsidiary which was less than $0.1 million and was reflected in other income (expense), net, in the consolidated statement of operations.
	In March 2013, the FASB issued ASU 2013-05, “Parent's Accounting for the Cumulative Translation Adjustment upon Derecognition of Certain Subsidiaries or Groups of Assets within a Foreign Entity or of an Investment in a Foreign Entity.” ASU 2013-05 clarifies the application of GAAP to the release of cumulative translation adjustments related to changes of ownership in or within foreign entities, including step acquisitions. This new guidance is effective for annual reporting periods beginning on or after December 15, 2013 and subsequent interim periods. We do not anticipate this pronouncement to have a material impact on our consolidated financial statements.
	In July 2013, the FASB issued ASU 2013-11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carry-forward, a Similar Tax Loss, or a Tax Credit Carryforward Exists.” ASU 2013-11 clarifies guidance and eliminates diversity in practice on the presentation of unrecognized tax benefits when a net operating loss carry-forward, a similar tax loss, or a tax credit carry-forward exists at the reporting date. This new guidance is effective for annual reporting periods beginning on or after December 15, 2013 and subsequent interim periods. We are currently assessing the impact, if any, on our consolidated financial statements.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Summary of Significant Accounting Policies [Abstract]	'
Summary of the annual changes in allowance for doubtful accounts	'
	The following table summarizes the annual changes in our allowance for doubtful accounts (in thousands):
	Balance at December 31, 2010	$	330
	Change in provision charged to expense		9
	Write-off of uncollectible accounts		(2	)
	Balance at December 31, 2011	$	337
	Change in provision charged to expense		151
	Write-off of uncollectible accounts		-
	Balance at December 31, 2012	$	488
	Change in provision charged to expense		(139	)
	Write-off of uncollectible accounts		(36	)
	Balance at December 31, 2013	$	313
Schedule of inventory	'
	Inventories are stated at the lower of cost or market, using the first-in-first-out method, and consisted of the following at December 31 (in thousands, net of allowances):
		2013			2012
	Raw materials	$	4,521		$	5,424
	Work in progress		2,429			2,186
	Finished goods		5,070			3,469
		$	12,020		$	11,079
Summary of depreciation period of property and equipment	'
	Property and equipment is stated at cost and is depreciated using the straight-line method over the estimated useful lives of the assets, as follows (in years):
	Equipment		10-Feb
	Demonstration units		5-Mar
	Computers and purchased software		3-Feb
	Furnitures and fixtures		5-Feb
Schedule of accrued liabilities	'
	Accrued expenses consist of the following at December 31 (in thousands):
		2013			2012
	Compensation, severance and benefits	$	2,685		$	2,351
	Warranty liability		529			694
	Taxes		483			320
	Professional fees		759			502
	Other		1,127			1,081
		$	5,583		$	4,948
Changes in the Company's warranty liability	'
	Changes in the Company’s warranty liability are as follows (in thousands):
	Balance at December 31, 2010	$	734
	Warranty expense		742
	Warranty charges incurred		(863	)
	Balance at December 31, 2011	$	613
	Warranty expense		1,294
	Warranty charges incurred		(1,152	)
	Balance at December 31, 2012	$	755
	Warranty expense		589
	Warranty charges incurred		(782	)
	Balance at December 31, 2013	$	562
	Warranty liability included in accrued expenses	$	529
	Long term warranty liability		33
	Balance at December 31, 2013	$	562
Summary of long term liabilities	'
	Long term liabilities consisted of the following at December 31 (in thousands):
		2013			2012
	Deferred revenue	$	601		$	533
	Technology licensing agreement		88			100
	Warranty liability		33			61
	Sublease deposits		19			19
		$	741		$	713
Details of stock-based compensation	'
	Details of our stock-based compensation include the following (in thousands):
		2013			2012			2011
	Stock-based compensation expense by caption:
	Cost of product revenue	$	254		$	216		$	199
	Cost of service and other revenue		116			70			79
	Research and development		204			153			166
	Selling and marketing		587			484			455
	General and administrative		539			486			807
		$	1,700		$	1,409		$	1,706
	Stock-based compensation expense by type of award:
	Stock options	$	1,488		$	1,213		$	1,707
	Restricted stock awards		212			196			(1	)
		$	1,700		$	1,409		$	1,706
Assumption used in Black Scholes model	'
	Assumptions used in the Black-Scholes model for our stock plans are presented below:
		2013			2012			2011
	Weighted average expected life in years	6.35 years			6.83 years			6.22 years
	Weighted average expected volatility		76	%		77	%		76	%
	Volatility Range		75%-76	%		75%-78	%		75%-76	%
	Risk-free interest rate range		1.13%-2.38	%		0.63%-1.00	%		1.00%-2.25	%
Customer concentration risk revenue percentages	'
	The following customers accounted for a significant percentage of Active Power’s total revenue during each of the years ended December 31:
		2013			2012			2011
	Caterpillar		14	%		13	%		16	%
	Hewlett Packard		22	%		35	%		36	%
	European based IT Customer		-			12	%		-
Basic and diluted net loss per share	'
	The following table sets forth the computation of basic and diluted net loss per share (in thousands) for the years ended December 31:
		2013			2012			2011
	Net loss	$	(8,351	)	$	(1,922	)	$	(7,094	)
	Basic and diluted:
	Weighted-average shares of common stock outstanding used in computing basic and diluted net loss per share		19,329			18,584			16,104
	Basic and diluted net loss per share	$	(0.43	)	$	(0.10	)	$	(0.44	)

Property_and_Equipment_Tables

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2013
Property and Equipment [Abstract]	'
Summary of property and equipment	'
	Property and equipment consists of the following at December 31 (in thousands):
		2013			2012
	Equipment	$	9,168		$	10,298
	Demonstration units		1,470			1,828
	Computers and purchased software		3,273			4,251
	Furnitures and fixtures		380			444
	Leasehold improvements		7,216			7,662
	Construction in progress		458			188
			21,965			24,671
	Accumulated depreciation		(18,909	)		(22,213	)
		$	3,056		$	2,458

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2013
Stockholders' Equity [Abstract]	'
Summary of common stock option activity	'
	A summary of common stock option activity is as follows:
		Number of Shares			Weighted-Average Exercise Price		Weighted-Average Contractual Life (in years)
	Outstanding at December 31, 2012		1,882,584		$	6.67
	Granted		1,470,200			3.86
	Exercised		(200,025	)		3.56
	Canceled		(745,095	)		6.57
	Outstanding at December 31, 2013		2,407,664		$	5.27		6.47
	Vested and expected to vest at December 31, 2013		1,982,004		$	5.62		5.99
	Exercisable at December 31, 2013		1,070,423		$	6.89		4.01
Summary of activity of restricted stock during the period	'
	In 2013 and 2012, we issued approximately 6,000 and 248,000 restricted shares, respectively, to directors and employees of the Company. The restrictions lapse as the shares vest in equal quarterly installments over a four year period from the date of issuance. We recorded stock compensation expense related to restricted share units of $0.2 million in 2013. A summary of our restricted, or non-vested, shares is as follows:
		Number of Shares			Weighted-Average Grant Date Fair Value
	Outstanding at December 31, 2012		200,071		$	3.81
	Granted		6,000			4.01
	Vested		(82,248	)		3.81
	Canceled		(70,785	)		3.67
	Outstanding at December 31, 2013		53,038		$	4

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Taxes [Abstract]	'
Significant components of deferred taxes	'
	Significant components of the Company’s deferred taxes as of December 31 are as follows (in thousands):
		2013			2012
	Deferred tax assets:
	Current deferred tax assets
	Reserves and allowances	$	1,177		$	1,338
	Deferred Rent		55
	Deferred revenue		328			267
	Valuation allowance for current deferred tax assets		(1,558	)		(1,604	)
	Net current deferred tax assets	$	2		$	1
	Noncurrent deferred tax assets
	Acquired technology		695			791
	Capital expenses		1,624			1,850
	Stock compensation		699			706
	Net operating loss and tax credit carryforwards		84,356			78,191
	Valuation allowance for noncurrent deferred tax assets		(87,263	)		(81,433	)
	Net noncurrent deferred tax assets	$	111		$	105
	Deferred tax liabilities:
	Current deferred tax liabilities
	Prepaid expenses		(113	)		(106	)
	Total current deferred tax liabilities	$	(113	)	$	(106	)
	Net current deferred tax aset (liability)	$	(111	)	$	(105	)
	Net noncurrent deferred tax aset (liability)	$	111		$	105
	Net deferred taxes	$	-		$	-
Income tax rate reconciliation	'
	The Company’s provision for income taxes differs from the expected tax benefit amount computed by applying the statutory federal income tax rate of 34% to income before taxes due to the following:
		Year Ended December 31,
		2013			2012			2011
	Federal statutory rate		(34.0	)%		(34.0	)%		(34.0	)%
	State taxes, net of federal benefit		(13.5	)		7.2			1.8
	R&D credits		(5.6	)		1.3			(1.2	)
	Stock compensation		6.2			14.5			10
	Effect of foreign operations		(20.5	)		157.3			2.5
	Expiration of net operating losses		-			63.2			-
	Permanent items and other		(1.9	)		6.8			0.1
	Change in valuation allowance		69.3			(216.3	)		21
			-	%		-	%		0.2	%
Reconciliation of unrecognized tax benefits	'
	The Company recognized no material adjustment in the liability for unrecognized income tax benefits. The reconciliation of the Company’s unrecognized tax benefits at the beginning and end of the year is as follows:
	Balance at January 1, 2013	$	1,677
	Additions based on tax positions related to the current year		290
	Additions for tax positions of prior years		23
	Balance at December 31, 2013	$	1,990

Commitments_Tables

Commitments (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments [Abstract]	'
Future minimum payments	'
	Future minimum payments under these leases at December 31, 2013 are as follows (in thousands):
		Rental payments
	2014	$	1,228
	2015		1,193
	2016		1,068
	2017		113
	2018		72
	Total future minimum lease payments	$	3,674

Geographic_Information_Tables

Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2013
Geographic Information [Abstract]	'
Revenues from foreign countries	'
	Revenues for the year ended December 31 were as follows (in thousands):
		2013		2012
	Americas	$	50,365	$	48,190
	Europe, Middle East and Africa		6,941		21,917
	Asia		4,393		6,208
	Total	$	61,699	$	76,315

Selected_Quarterly_Consolidate1

Selected Quarterly Consolidated Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2013
Selected Quarterly Consolidated Financial Data (unaudited) [Abstract]	'
Quarterly consolidated statement of operations	'
	The following tables present selected unaudited consolidated statement of operations information for each of the quarters in the years ended December 31, 2013 and 2012 (in thousands, except per share data):
		For the Quarter Ended
	Year Ended December 31, 2013	31-Dec			30-Sep			30-Jun		31-Mar
	Selected consolidated statement of operations information:
	Total revenue	$	13,926		$	13,154		$	20,195	$	14,424
	Total cost of goods sold	$	9,750		$	9,210		$	13,273	$	10,070
	Gross profit	$	4,176		$	3,944		$	6,922	$	4,354
	Operating expenses	$	7,990		$	6,909		$	6,412	$	5,702
	Operating profit (loss)	$	(3,814	)	$	(2,965	)	$	510	$	(1,348	)
	Net income (loss)	$	(4,127	)	$	(3,135	)	$	332	$	(1,421	)
	Basic and diluted new income (loss) per share	$	(0.21	)	$	(0.16	)	$	0.02	$	(0.07	)
	Selected consolidated balance sheet information:
	Current assets	$	34,556		$	39,110		$	45,722	$	42,019
	Total assets	$	37,907		$	42,263		$	49,052	$	44,748
	Current liabilities	$	16,860		$	18,194		$	22,758	$	19,208
	Working capital	$	17,696		$	20,916		$	22,964	$	22,811
	Long term obligations	$	741		$	737		$	689	$	774
	Stockholders' equity	$	20,306		$	23,332		$	25,605	$	24,766
		For the Quarter Ended
	Year Ended December 31, 2012	31-Dec			30-Sep			30-Jun		31-Mar
	Selected consolidated statement of operations information:
	Total revenue	$	15,247		$	19,611		$	21,659	$	19,798
	Total cost of goods sold	$	9,227		$	13,996		$	13,887	$	14,491
	Gross profit	$	6,020		$	5,615		$	7,772	$	5,307
	Operating expenses	$	6,329		$	6,463		$	7,269	$	6,379
	Operating profit (loss)	$	(309	)	$	(848	)	$	503	$	(1,072	)
	Net income (loss)	$	(418	)	$	(847	)	$	490	$	(1,147	)
	Basic and diluted new income (loss) per share	$	(0.02	)	$	(0.04	)	$	0.03	$	(0.06	)
	Selected consolidated balance sheet information:
	Current assets	$	43,032		$	42,950		$	44,334	$	44,352
	Total assets	$	45,799		$	46,135		$	47,787	$	47,892
	Current liabilities	$	19,087		$	19,501		$	20,812	$	21,551
	Working capital	$	23,945		$	23,449		$	23,522	$	22,801
	Long term obligations	$	713		$	798		$	834	$	748
	Stockholders' equity	$	25,999		$	18,900		$	19,937	$	20,519

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Summary of Significant Accounting Policies [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Reverse stock split	'	'	'	'	'	'	'	'	'five for one	'	'
Revenue Recognition [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Duration period of product delivery related to certain services on design and consultation	'	'	'	'	'	'	'	'	'6 months	'	'
Delivery period for EMAs, consumables, and repair, maintenance or consulting services, minimum	'	'	'	'	'	'	'	'	'1 year	'	'
Delivery period for EMAs, consumables, and repair, maintenance or consulting services, maximum	'	'	'	'	'	'	'	'	'5 years	'	'
Allowance for Doubtful Accounts [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Accounts receivable, allowance for doubtful accounts	$313,000	'	'	'	$488,000	'	'	'	$313,000	$488,000	'
Annual changes in allowance for doubtful accounts [Roll Forward]	'	'	'	'	'	'	'	'	'	'	'
Balance at the beginning of the period	'	'	'	488,000	'	'	'	337,000	488,000	337,000	330,000
Additions charged to expense	'	'	'	'	'	'	'	'	-139,000	151,000	9,000
Write-off of uncollectible accounts	'	'	'	'	'	'	'	'	-36,000	0	-2,000
Balance at the end of the period	313,000	'	'	'	488,000	'	'	'	313,000	488,000	337,000
Allowance for doubtful accounts standard terms	'	'	'	'	'	'	'	'	'30 days	'	'
Inventories [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Raw materials	4,521,000	'	'	'	5,424,000	'	'	'	4,521,000	5,424,000	'
Work in progress	2,429,000	'	'	'	2,186,000	'	'	'	2,429,000	2,186,000	'
Finished goods	5,070,000	'	'	'	3,469,000	'	'	'	5,070,000	3,469,000	'
Inventories	12,020,000	'	'	'	11,079,000	'	'	'	12,020,000	11,079,000	'
Accrued Expenses [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Compensation, severance and benefits	2,685,000	'	'	'	2,351,000	'	'	'	2,685,000	2,351,000	'
Warranty liability	529,000	'	'	'	694,000	'	'	'	529,000	694,000	'
Taxes	483,000	'	'	'	320,000	'	'	'	483,000	320,000	'
Professional fees	759,000	'	'	'	502,000	'	'	'	759,000	502,000	'
Other	1,127,000	'	'	'	1,081,000	'	'	'	1,127,000	1,081,000	'
Accrued expenses	5,583,000	'	'	'	4,948,000	'	'	'	5,583,000	4,948,000	'
Changes in the Company's warranty liability [Roll Forward]	'	'	'	'	'	'	'	'	'	'	'
Balance at beginning of period	'	'	'	755,000	'	'	'	613,000	755,000	613,000	734,000
Warranty expense	'	'	'	'	'	'	'	'	589,000	1,294,000	742,000
Warranty charges incurred	'	'	'	'	'	'	'	'	-782,000	-1,152,000	-863,000
Balance at ending of period	562,000	'	'	'	755,000	'	'	'	562,000	755,000	613,000
Warrant liability included in accrued expenses	529,000	'	'	'	694,000	'	'	'	529,000	694,000	'
Long term warranty liability	33,000	'	'	'	61,000	'	'	'	33,000	61,000	'
Warranty accrual at end of period	562,000	'	'	'	'	'	'	'	562,000	'	'
Long Term Liabilities [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Deferred revenue	601,000	'	'	'	533,000	'	'	'	601,000	533,000	'
Technology licensing agreement	88,000	'	'	'	100,000	'	'	'	88,000	100,000	'
Warranty liability	33,000	'	'	'	61,000	'	'	'	33,000	61,000	'
Sublease deposits	19,000	'	'	'	19,000	'	'	'	19,000	19,000	'
Long term liabilities	741,000	737,000	689,000	774,000	713,000	798,000	834,000	748,000	741,000	713,000	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Stock-based compensation expense	'	'	'	'	'	'	'	'	1,700,000	1,409,000	1,706,000
Stock-based compensation expense, capitalized and remained in inventory	'	'	'	'	'	'	'	'	0	0	'
Average expected forfeitures (in hundredths)	'	'	'	'	'	'	'	'	18.90%	17.00%	15.30%
Fair value assumptions used in Black-Scholes model [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Weighted average expected life in years	'	'	'	'	'	'	'	'	'6 years 4 months 6 days	'6 years 9 months 29 days	'6 years 2 months 19 days
Weighted average expected volatility (in hundredths)	'	'	'	'	'	'	'	'	76.00%	77.00%	76.00%
Volatility range, minimum (in hundredths)	'	'	'	'	'	'	'	'	75.00%	75.00%	75.00%
Volatility range, maximum (in hundredths)	'	'	'	'	'	'	'	'	76.00%	78.00%	76.00%
Risk-free interest rate range, minimum (in hundredths)	'	'	'	'	'	'	'	'	1.13%	0.63%	1.00%
Risk-free interest rate range, maximum (in hundredths)	'	'	'	'	'	'	'	'	2.38%	1.00%	2.25%
Advertising Costs [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Advertising expense	'	'	'	'	'	'	'	'	23,000	36,000	90,000
Net Income (Loss) Per Share [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Net loss	-4,127,000	-3,135,000	332,000	-1,421,000	-418,000	-847,000	490,000	-1,147,000	-8,351,000	-1,922,000	-7,094,000
Basic and diluted [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Weighted-average shares of common stock outstanding used in computing basic and diluted net loss per share (in shares)	'	'	'	'	'	'	'	'	19,329,000	18,584,000	16,104,000
Basic and diluted net loss per share (in dollars per share)	'	'	'	'	'	'	'	'	($0.43)	($0.10)	($0.44)
Recent Accounting Pronouncements [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Other income (expense), net	'	'	'	'	'	'	'	'	100,000	'	'
Stock Options [Member]	'	'	'	'	'	'	'	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Antidilutive stock not included in net loss per share (in shares)	'	'	'	'	'	'	'	'	2,407,664	1,882,584	1,943,648
Restricted Stock [Member]	'	'	'	'	'	'	'	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Antidilutive stock not included in net loss per share (in shares)	'	'	'	'	'	'	'	'	53,038	200,071	'
Revenue [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Benchmark description	'	'	'	'	'	'	'	'	'10% of our revenues	'	'
Revenue [Member] | EMEA [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Concentration risk percentage (in hundredths)	'	'	'	'	'	'	'	'	'	10.00%	'
Revenue [Member] | Customer Concentration Risk [Member] | Caterpillar [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Concentration risk percentage (in hundredths)	'	'	'	'	'	'	'	'	14.00%	13.00%	16.00%
Revenue [Member] | Customer Concentration Risk [Member] | Hewlett Packard [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Concentration risk percentage (in hundredths)	'	'	'	'	'	'	'	'	22.00%	35.00%	36.00%
Revenue [Member] | Customer Concentration Risk [Member] | European Based IT Customer [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Concentration risk percentage (in hundredths)	'	'	'	'	'	'	'	'	0.00%	12.00%	0.00%
Outstanding Receivables [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Benchmark description	'	'	'	'	'	'	'	'	'10% of our accounts receivable	'10% of our accounts receivable	'
Outstanding Receivables [Member] | Caterpillar [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Concentration risk percentage (in hundredths)	'	'	'	'	'	'	'	'	23.00%	'	'
Outstanding Receivables [Member] | Hewlett Packard [Member]	'	'	'	'	'	'	'	'	'	'	'
Concentration Risk [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Concentration risk percentage (in hundredths)	'	'	'	'	'	'	'	'	'	23.00%	'
Stock Options [Member]	'	'	'	'	'	'	'	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Stock-based compensation expense	'	'	'	'	'	'	'	'	1,488,000	1,213,000	1,707,000
Restricted stock awards [Member]	'	'	'	'	'	'	'	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Stock-based compensation expense	'	'	'	'	'	'	'	'	212,000	196,000	-1,000
Cost of product revenue [Member]	'	'	'	'	'	'	'	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Stock-based compensation expense	'	'	'	'	'	'	'	'	254,000	216,000	199,000
Cost of service and other revenue [Member]	'	'	'	'	'	'	'	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Stock-based compensation expense	'	'	'	'	'	'	'	'	116,000	70,000	79,000
Research and Development Expense [Member]	'	'	'	'	'	'	'	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Stock-based compensation expense	'	'	'	'	'	'	'	'	204,000	153,000	166,000
Selling and Marketing Expense [Member]	'	'	'	'	'	'	'	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Stock-based compensation expense	'	'	'	'	'	'	'	'	587,000	484,000	455,000
General and Administrative Expense [Member]	'	'	'	'	'	'	'	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Stock-based compensation expense	'	'	'	'	'	'	'	'	539,000	486,000	807,000
Power Quality Products [Member]	'	'	'	'	'	'	'	'	'	'	'
Warranty Liabilities [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Warranty period from date of commissioning	'	'	'	'	'	'	'	'	'12 months	'	'
Warranty period granted from date of shipment	'	'	'	'	'	'	'	'	'18 months	'	'
Minimum [Member] | Caterpillar [Member]	'	'	'	'	'	'	'	'	'	'	'
Warranty Liabilities [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Warranty period granted from date of shipment	'	'	'	'	'	'	'	'	'12 months	'	'
Maximum [Member] | Caterpillar [Member]	'	'	'	'	'	'	'	'	'	'	'
Warranty Liabilities [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Warranty period granted from date of shipment	'	'	'	'	'	'	'	'	'36 months	'	'
Equipment [Member] | Minimum [Member]	'	'	'	'	'	'	'	'	'	'	'
Property and Equipment [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Estimated useful lives of property and equipment	'	'	'	'	'	'	'	'	'2 years	'	'
Equipment [Member] | Maximum [Member]	'	'	'	'	'	'	'	'	'	'	'
Property and Equipment [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Estimated useful lives of property and equipment	'	'	'	'	'	'	'	'	'10 years	'	'
Demonstration units [Member] | Minimum [Member]	'	'	'	'	'	'	'	'	'	'	'
Property and Equipment [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Estimated useful lives of property and equipment	'	'	'	'	'	'	'	'	'3 years	'	'
Demonstration units [Member] | Maximum [Member]	'	'	'	'	'	'	'	'	'	'	'
Property and Equipment [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Estimated useful lives of property and equipment	'	'	'	'	'	'	'	'	'5 years	'	'
Computers and purchased software [Member] | Minimum [Member]	'	'	'	'	'	'	'	'	'	'	'
Property and Equipment [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Estimated useful lives of property and equipment	'	'	'	'	'	'	'	'	'2 years	'	'
Computers and purchased software [Member] | Maximum [Member]	'	'	'	'	'	'	'	'	'	'	'
Property and Equipment [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Estimated useful lives of property and equipment	'	'	'	'	'	'	'	'	'3 years	'	'
Furnitures and Fixtures [Member] | Minimum [Member]	'	'	'	'	'	'	'	'	'	'	'
Property and Equipment [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Estimated useful lives of property and equipment	'	'	'	'	'	'	'	'	'2 years	'	'
Furnitures and Fixtures [Member] | Maximum [Member]	'	'	'	'	'	'	'	'	'	'	'
Property and Equipment [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Estimated useful lives of property and equipment	'	'	'	'	'	'	'	'	'5 years	'	'
Level 1 [Member]	'	'	'	'	'	'	'	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Cash and cash equivalents	$3,100	'	'	'	$3,100	'	'	'	$3,100	$3,100	'

Property_and_Equipment_Details

Property and Equipment (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Property and Equipment [Line Items]	'	'
Property and equipment, gross	$21,965	$24,671
Accumulated depreciation	-18,909	-22,213
Property and equipment, net	3,056	2,458
Equipment [Member]	'	'
Property and Equipment [Line Items]	'	'
Property and equipment, gross	9,168	10,298
Demonstration Units [Member]	'	'
Property and Equipment [Line Items]	'	'
Property and equipment, gross	1,470	1,828
Computers and Purchased Software [Member]	'	'
Property and Equipment [Line Items]	'	'
Property and equipment, gross	3,273	4,251
Furnitures and Fixtures [Member]	'	'
Property and Equipment [Line Items]	'	'
Property and equipment, gross	380	444
Leasehold Improvements [Member]	'	'
Property and Equipment [Line Items]	'	'
Property and equipment, gross	7,216	7,662
Construction in Progress [Member]	'	'
Property and Equipment [Line Items]	'	'
Property and equipment, gross	$458	$188

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)

0 Months Ended

12 Months Ended

12 Months Ended

In Thousands, except Share data, unless otherwise specified

Mar. 31, 2012

Feb. 28, 2010

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

31-May-12

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

2000 and 2010 Stock Incentive Plans [Member]

Common Stock [Member]

Common Stock [Member]

Stock Options [Member]

Restricted (non-vested) Shares [Member]

Restricted (non-vested) Shares [Member]

Stock Options and Restricted Stock [Member]

Shares Added to 2010 Stock Incentive Plan [Member]

Shares Added to 2010 Stock Incentive Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Preferred stock authorized (in shares)

'

'

2,000,000

2,000,000

'

'

'

'

'

'

'

'

Shares reserved for future issuance (in shares)

'

'

'

'

'

'

3,667,109

1,700,000

'

'

'

2,470,083

Shares available for future grants of awards (in shares)

'

'

1,185,026

'

'

'

'

'

'

'

'

'

Shares of common stock sold (in shares)

2,900,000

2,700,000

19,452,000

19,171,000

'

'

'

'

'

'

'

'

Purchase price per share (in dollars per share)

$3.40

$3.75

'

'

'

'

'

'

'

'

'

'

Proceeds from private placement, net of fees and expenses

$9,600

$9,000

$0

$9,750

$0

'

'

'

'

'

'

'

Authorized shares of common stock for issuance (in shares)

'

'

'

'

'

5,682,296

'

'

'

'

'

'

Vesting period

'

'

'

'

'

'

'

'

'4 years

'3 years

'

'

Term of awards

'

'

'

'

'

'

'

'

'10 years

'

'

'

Shares offered to officers and/or employees (in shares)

'

'

'

'

'

'

'

'

'

6,000

248,000

'

Stockholders_Equity_Stock_Opti

Stockholders' Equity, Stock Options Activity (Details) (Stock Options [Member], USD $)	12 Months Ended
	Dec. 31, 2013
Stock Options [Member]	'
Share-based compensation options outstanding [Roll Forward]	'
Outstanding at the beginning of the period (in shares)	1,882,584
Granted (in shares)	1,470,200
Exercised (in shares)	-200,025
Canceled (in shares)	-745,095
Outstanding at the end of the period (in shares)	2,407,664
Vested and expected to vest at the end of the period (in shares)	1,982,004
Exercisable number of shares at the end of the period (in shares)	1,070,423
Share-based compensation options weighted average exercise price [Roll Forward]	'
Outstanding at the beginning of the period (in dollars per share)	$6.67
Granted (in dollars per share)	$3.86
Exercised (in dollars per share)	$3.56
Canceled (in dollars per share)	$6.57
Outstanding at the end of the period (in dollars per share)	$5.27
Weighted average exercise price vested and expected to vest (in dollars per share)	$5.62
Weighted average exercise price of shares exercisable at the end of the period (in dollars per share)	$6.89
Weighted average contractual term of shares outstanding	'6 years 5 months 19 days
Weighted average contractual term of shares vested and expected to vest at end of the period	'5 years 11 months 26 days
Weighted average contractual term of shares exercisable at the end of the period	'4 years 0 months 4 days

Stockholders_Equity_Stock_Opti1

Stockholders' Equity, Stock Options, by Exercise Price Range (Details) (USD $)	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'	'
Weighted average grant date fair value (in dollars per share)	$2.60	$2.60	$6.76
Intrinsic value of options exercised	$0.10	$0.10	$0.60
Aggregate intrinsic value of options outstanding	0.4	'	'
Aggregate intrinsic value of options exercisable	$0.10	'	'

Stockholders_Equity_Restricted

Stockholders' Equity, Restricted (non-vested) Shares (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Restricted (non-vested) Shares [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Restricted Stock or Unit Expense	$0.20	'	'
Share-based Compensation other than options [Roll Forward]	'	'	'
Outstanding at the beginning of the period (in shares)	200,071	'	'
Granted (in shares)	6,000	'	'
Vested (in shares)	-82,248	'	'
Canceled (in shares)	-70,785	'	'
Outstanding at the end of the period (in shares)	53,038	200,071	'
Share-based compensation other than options grant date fair value [Roll Forward]	'	'	'
Weighted average grant date fair value at the beginning of the period (in dollars per share)	$3.81	'	'
Granted (in dollars per share)	$4.01	'	'
Vested (in dollars per share)	$3.81	'	'
Canceled (in dollars per share)	$3.67	'	'
Weighted average grant date fair value at the end of the period (in dollars per share)	$4	$3.81	'
Total unrecognized compensation cost	0.2	'	'
Unrecognized compensation cost, weighted-average vesting period	'2 years 1 month 6 days	'	'
Fair value of restricted share units vested	0.3	1	'
Stock Options [Member]	'	'	'
Share-based compensation other than options grant date fair value [Roll Forward]	'	'	'
Total unrecognized compensation cost	2.4	'	'
Unrecognized compensation cost, weighted-average vesting period	'3 years 1 month 6 days	'	'
Fair value of restricted share units vested	$1.40	$1.70	$0.90

Income_Taxes_Details

Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Taxes [Abstract]	'	'	'
Federal net operating loss carryforwards	$217,000,000	'	'
Current deferred tax assets [Abstract]	'	'	'
Reserves and allowances	1,177,000	1,338,000	'
Deferred rent	55,000	'	'
Deferred revenue	328,000	267,000	'
Valuation allowance for current deferred tax assets	-1,558,000	-1,604,000	'
Net current deferred tax assets	2,000	1,000	'
Noncurrent deferred tax assets [Abstract]	'	'	'
Acquired technology	695,000	791,000	'
Capital expenses	1,624,000	1,850,000	'
Stock compensation	699,000	706,000	'
Net operating loss and tax credit carryforwards	84,356,000	78,191,000	'
Valuation allowance for noncurrent deferred tax assets	-87,263,000	-81,433,000	'
Net noncurrent deferred tax assets	111,000	105,000	'
Current deferred tax liabilities [Abstract]	'	'	'
Prepaid expenses	-113,000	-106,000	'
Total current deferred tax liabilities	-113,000	-106,000	'
Net current deferred tax asset (liability)	-111,000	-105,000	'
Net noncurrent deferred tax asset (liability)	111,000	105,000	'
Net deferred taxes	0	0	'
Valuation Allowance [Line Items]	'	'	'
Change in valuation allowance	5,800,000	'	'
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]	'	'	'
Federal statutory rate (in hundredths)	-34.00%	-34.00%	-34.00%
State taxes, net of federal benefit (in hundredths)	-13.50%	7.20%	1.80%
R&D credits (in hundredths)	-5.60%	1.30%	-1.20%
Stock compensation (in hundredths)	6.20%	14.50%	10.00%
Effect of foreign operations (in hundredths)	-20.50%	157.30%	2.50%
Expiration of net operating losses (in hundredths)	0.00%	63.20%	0.00%
Permanent items and other (in hundredths)	-1.90%	6.80%	0.10%
Change in valuation allowance (in hundredths)	69.30%	-216.30%	21.00%
Effective income tax rate (in hundredths)	0.00%	0.00%	0.20%
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]	'	'	'
Balance at beginning of period	1,677,000	'	'
Additions based on tax positions related to the current year	290,000	'	'
Additions for tax positions of prior years	23,000	'	'
Balance at end of period	1,990,000	1,677,000	'
Tax Benefits for Stock Option Deductions [Member]	'	'	'
Valuation Allowance [Line Items]	'	'	'
Valuation allowance	6,400,000	'	'
Research Tax Credit Carryforward [Member]	'	'	'
Tax Credit Carryforward [Line Items]	'	'	'
Tax credit carryforwards	$3,700,000	'	'

Commitments_Details

Commitments (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Real Estate Properties [Line Items]	'	'	'
Rent expense offset by sublease	'	'	$300,000
Net deferred rent	100,000	0	0
Net rent expense	1,700,000	1,700,000	1,300,000
Future minimum payments [Abstract]	'	'	'
2014	1,228,000	'	'
2015	1,193,000	'	'
2016	1,068,000	'	'
2017	113,000	'	'
2018	72,000	'	'
Total future minimum lease payments	3,674,000	'	'
Commitments to purchase inventory and other items [Abstract]	'	'	'
2014	3,200,000	'	'
2015	25,000	'	'
2016	25,000	'	'
2017	25,000	'	'
Total purchase commitments	$3,300,000	'	'
Severance Benefits Agreements [Abstract]	'	'	'
Duration period in change in executive officer's employment	'12 months	'	'
Chief Executive Officer [Member]	'	'	'
Severance Benefits Agreements [Abstract]	'	'	'
Duration period of payment of salary and health benefits after termination	'12 months	'	'
Other Executive Officer [Member]	'	'	'
Severance Benefits Agreements [Abstract]	'	'	'
Duration period of payment of salary and health benefits after termination	'6 months	'	'
Subleased to third party [Member]	'	'	'
Real Estate Properties [Line Items]	'	'	'
Facilities usage (in square feet)	'	'	31,000
Administration, marketing and engineering [Member]	'	'	'
Real Estate Properties [Line Items]	'	'	'
Facilities usage (in square feet)	12,000	'	'
Expansion of our manufacturing facility [Member]	'	'	'
Real Estate Properties [Line Items]	'	'	'
Facilities usage (in square feet)	'	'	26,195

Employee_Benefit_Plan_Details

Employee Benefit Plan (Details) (401 (k) Plan [Member])	12 Months Ended
	Dec. 31, 2013
401 (k) Plan [Member]	'
Defined Benefit Plan Disclosure [Line Items]	'
Vesting period	'5 years

Geographic_Information_Details

Geographic Information (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	Country
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Revenues	$61,699,000	$76,315,000	$75,482,000
Number of foreign countries from which revenue derived	34	'	'
Net assets	5,800,000	'	'
Americas [Member]	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Revenues	50,365,000	48,190,000	48,653,000
EMEA [Member]	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Revenues	6,941,000	21,917,000	19,060,000
Asia [Member]	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'
Revenues	$4,393,000	$6,208,000	$7,769,000

Guarantees_Details

Guarantees (Details) (Performance Guarantee [Member], USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Performance Guarantee [Member]	'	'
Guarantor Obligations [Line Items]	'	'
Performance guarantees outstanding to customers	$0.50	$0

Revolving_Credit_Facility_Deta

Revolving Credit Facility (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010
Line of Credit Facility Inventory Borrowing Rates [Line Items]	'	'	'
Borrowing base sublimits, U.K.(United Kingdom) accounts receivable	$5,000,000	'	'
Borrowing base sublimits, Inventory	3,500,000	'	'
Borrowing base sublimits, Purchase orders	1,500,000	'	'
Increase in rate on finance charges or interest rates, as applicable, in the event of default (in hundredths)	5.00%	'	'
Increase in rate on collateral handling fees in the event of default (in hundredths)	0.50%	'	'
Letter of Credit [Member]	'	'	'
Line of Credit Facility Inventory Borrowing Rates [Line Items]	'	'	'
Maximum borrowing capacity	1,500,000	'	'
Revolving Line of Credit [Member]	'	'	'
Line of Credit Facility Inventory Borrowing Rates [Line Items]	'	'	'
Maximum borrowing capacity	15,625,000	'	'
Loan facility term	'2 years	'	'
Aggregate percentage of the facility provision available during the "Streamline Period" (in hundredths)	80.00%	'	'
Minimum restricted cash and cash equivalents required for the facility	6,250,000	'	'
Minimum duration period to maintain cash and cash equivalents	'30 days	'	'
Line of credit facility outstanding	5,500,000	5,500,000	2,500,000
Interest rate during period (in hundredths)	5.25%	'	'
Additional borrowing base	3,900,000	'	'
Maturity date	5-Aug-14	'	'
Repayment terms on purchase orders borrowings	'120 days	'	'
Minimum liquidity ratio requirement	'1.25:1	'	'
Minimum liquidity ratio considered for steam line period	'1.75:1	'	'
Minimum number of consecutive days required to maintain a liquidity ratio to be considered in a streamline period	'60 days	'	'
Revolving Line of Credit [Member] | Minimum [Member]	'	'	'
Line of Credit Facility Inventory Borrowing Rates [Line Items]	'	'	'
Current borrowing capacity	'	'	6,000,000
Revolving Line of Credit [Member] | Maximum [Member]	'	'	'
Line of Credit Facility Inventory Borrowing Rates [Line Items]	'	'	'
Current borrowing capacity	'	'	$12,500,000
SVB Streamline Period [Member]	'	'	'
Line of Credit Facility Inventory Borrowing Rates [Line Items]	'	'	'
Minimum prime interest rate (in hundredths)	4.00%	'	'
SVB Streamline Period [Member] | Inventory Borrowing Rates [Member]	'	'	'
Line of Credit Facility Inventory Borrowing Rates [Line Items]	'	'	'
Prime interest plus rate (in hundredths)	1.25%	'	'
SVB Streamline Period [Member] | Accounts Receivable Aged Borrowing Rates [Member]	'	'	'
Line of Credit Facility Inventory Borrowing Rates [Line Items]	'	'	'
Prime interest plus rate (in hundredths)	1.75%	'	'
SVB non Streamline Period [Member]	'	'	'
Line of Credit Facility Inventory Borrowing Rates [Line Items]	'	'	'
Minimum prime interest rate (in hundredths)	4.00%	'	'
SVB non Streamline Period [Member] | Inventory Borrowing Rates [Member]	'	'	'
Line of Credit Facility Inventory Borrowing Rates [Line Items]	'	'	'
Prime interest plus rate (in hundredths)	3.50%	'	'
SVB non Streamline Period [Member] | Accounts Receivable Aged Borrowing Rates [Member]	'	'	'
Line of Credit Facility Inventory Borrowing Rates [Line Items]	'	'	'
Prime interest plus rate (in hundredths)	2.00%	'	'

Selected_Quarterly_Consolidate2

Selected Quarterly Consolidated Financial Data (unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Selected consolidated statement of operations information [Abstract]	'	'	'	'	'	'	'	'	'	'	'	'
Total revenue	$13,926	$13,154	$20,195	$14,424	$15,247	$19,611	$21,659	$19,798	$61,699	$76,315	$75,482	'
Total cost of goods sold	9,750	9,210	13,273	10,070	9,227	13,996	13,887	14,491	42,303	51,601	57,581	'
Gross profit	4,176	3,944	6,922	4,354	6,020	5,615	7,772	5,307	19,396	24,714	17,901	'
Operating expenses	7,990	6,909	6,412	5,702	6,329	6,463	7,269	6,379	27,013	26,440	24,781	'
Operating profit (loss)	-3,814	-2,965	510	-1,348	-309	-848	503	-1,072	-7,617	-1,726	-6,880	'
Net income (loss)	-4,127	-3,135	332	-1,421	-418	-847	490	-1,147	-8,351	-1,922	-7,094	'
Basic and diluted net income (loss) per share (in dollars per share)	($0.21)	($0.16)	$0.02	($0.07)	($0.02)	($0.04)	$0.03	($0.06)	($0.43)	($0.10)	($0.44)	'
Selected consolidated balance sheet information [Abstract]	'	'	'	'	'	'	'	'	'	'	'	'
Current assets	34,556	39,110	45,722	42,019	43,032	42,950	44,334	44,352	34,556	43,032	'	'
Total assets	37,907	42,263	49,052	44,748	45,799	46,135	47,787	47,892	37,907	45,799	'	'
Current liabilities	16,860	18,194	22,758	19,208	19,087	19,501	20,812	21,551	16,860	19,087	'	'
Working capital	17,696	20,916	22,964	22,811	23,945	23,449	23,522	22,801	17,696	23,945	'	'
Long term obligations	741	737	689	774	713	798	834	748	741	713	'	'
Stockholders' equity	$20,306	$23,332	$25,605	$24,766	$25,999	$18,900	$19,937	$20,519	$20,306	$25,999	$16,292	$20,822

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	12 Months Ended					1 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2012	Feb. 28, 2010	Feb. 26, 2014
						Subsequent Event [Member]
						Common Stock [Member]
Subsequent Event [Line Items]	'	'	'	'	'	'
Number of common stock issued (in shares)	19,452,000	19,171,000	'	2,900,000	2,700,000	3,651,250
IPO price per share (in dollars per share)	'	'	'	$3.40	$3.75	$3.15
Proceed from stock issued	'	'	'	'	'	$10,500,000
Equity offering cost	$0	$187,000	$0	'	'	$1,000,000