Microbot Medical (MBOT) 10-Q 5 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Nov. 01, 2013
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'STEM	'
Entity Registrant Name	'STEMCELLS INC	'
Entity Central Index Key	'0000883975	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Smaller Reporting Company	'
Entity Common Stock, Shares Outstanding	'	54,971,174

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
Current assets:	'	'
Cash and cash equivalents	$20,955,293	$8,471,275
Marketable securities, current	'	13,900,678
Trade receivables	125,487	110,159
Other receivables	491,556	200,788
Prepaid assets	464,464	537,590
Deferred financing costs, current	51,808	'
Other assets, current	110,615	820,827
Total current assets	22,199,223	24,041,317
Property, plant and equipment, net	5,438,659	1,375,329
Deferred financing costs, non-current	32,571	'
Other assets, non-current	999,776	947,301
Goodwill	1,973,302	1,983,426
Other intangible assets, net	1,673,051	1,822,904
Total assets	32,316,582	30,170,277
Current liabilities:	'	'
Accounts payable	1,860,544	999,365
Accrued expenses and other current liabilities	2,303,506	2,707,441
Accrued wind-down expenses, current	'	1,102,762
Deferred revenue, current	67,588	74,426
Capital lease obligation, current	20,936	6,888
Deferred rent, current	28,050	'
Loan payable net of discount, current	3,602,972	'
Bonds payable, current	178,750	206,250
Total current liabilities	8,062,346	5,097,132
Bonds payable, non-current	'	125,000
Capital lease obligations, non-current	34,896	12,646
Loan payable net of discount, non-current	9,865,375	'
Fair value of warrant liability	8,420,954	9,265,365
Deposits and other long-term liabilities	512,320	216,439
Deferred rent, non-current	1,792,683	1,389,342
Deferred revenue, non-current	67,116	79,736
Total liabilities	28,755,690	16,185,660
Commitments and contingencies (Note 8)	'	'
Stockholders' equity:	'	'
Common stock, $0.01 par value; 75,000,000 shares authorized; issued and outstanding 42,044,839 at September 30, 2013 and 37,506,305 at December 31, 2012	420,449	375,063
Additional paid-in capital	383,537,795	374,507,552
Accumulated deficit	-380,567,957	-361,091,175
Accumulated other comprehensive income	170,605	193,177
Total stockholders' equity	3,560,892	13,984,617
Total liabilities and stockholders' equity	$32,316,582	$30,170,277

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares issued	42,044,839	37,506,305
Common stock, shares outstanding	42,044,839	37,506,305

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Operations (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenue:	'	'	'	'
Revenue from licensing agreements, grants and other	$52,798	$60,739	$159,773	$471,501
Revenue from product sales	271,994	203,256	730,916	685,364
Total revenue	324,792	263,995	890,689	1,156,865
Cost of product sales	85,743	71,891	230,157	208,127
Gross profit	239,049	192,104	660,532	948,738
Operating expenses:	'	'	'	'
Research and development	5,184,365	3,478,142	14,553,145	11,165,599
Selling, general and administrative	1,710,749	1,636,438	5,180,027	5,336,105
Wind-down expenses	'	154,742	61,837	199,799
Total operating expenses	6,895,114	5,269,322	19,795,009	16,701,503
Loss from operations	-6,656,065	-5,077,218	-19,134,477	-15,752,765
Other income (expense):	'	'	'	'
Change in fair value of warrant liability	-143,511	-11,239,465	425,570	-9,974,685
Interest income	136	2,372	8,772	9,393
Interest expense	-382,119	-11,392	-785,122	-40,014
Other income (expense), net	-10,094	-11,087	8,475	25,364
Total other expense, net	-535,588	-11,259,572	-342,305	-9,979,942
Net loss	($7,191,653)	($16,336,790)	($19,476,782)	($25,732,707)
Basic and diluted net loss per share	($0.17)	($0.54)	($0.49)	($0.99)
Weighted average number of common shares outstanding, basic and diluted	41,402,717	30,168,475	39,787,527	25,992,764

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (Loss) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Comprehensive Income [Abstract]	'	'	'	'
Net loss	($7,191,653)	($16,336,790)	($19,476,782)	($25,732,707)
Other comprehensive income (loss)	'	'	'	'
Foreign currency translation adjustments	206,120	98,706	-23,928	125,854
Unrealized gains (losses) on marketable securities	-425	587	1,356	3,210
Other comprehensive income (loss)	205,695	99,293	-22,572	129,064
Comprehensive loss	($6,985,958)	($16,237,497)	($19,499,354)	($25,603,643)

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Cash Flows (USD $)	9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012
Cash flows from operating activities:	'		'
Net loss	($19,476,782)		($25,732,707)
Adjustments to reconcile net loss to net cash used in operating activities:	'		'
Depreciation and amortization	730,504		759,527
Stock-based compensation	2,033,228		2,227,145
Amortization of debt discount and issuance costs	509,069		'
Gain on disposal of fixed assets	-34,946		'
Change in fair value of warrant liability	-425,570		9,974,685
Changes in operating assets and liabilities:	'		'
Accrued interest and other receivables	-364,940		19,432
Trade receivables	57,569		-40,584
Prepaid and other current assets	782,745		170,667
Other assets, non-current	-52,474		32,926
Accounts payable and accrued expenses	499,935		-1,613,123
Accrued wind-down expenses	-1,102,762		-817,110
Deferred revenue	-19,146		-665
Deferred rent	431,390		69,997
Net cash used in operating activities	-16,432,180		-14,949,810
Cash flows from investing activities:	'		'
Purchase of marketable securities	-527,967		-8,109,933
Proceeds from the maturity of marketable securities	14,430,000		5,362,000
Purchases of property, plant and equipment	-4,556,406		-19,729
Proceeds from sale of property, plant and equipment	38,500		'
Acquisition of other assets	-100,000		'
Net cash provided by (used in) investing activities	9,284,127		-2,767,662
Cash flows from financing activities:	'		'
Proceeds from issuance of common stock, net of issuance costs	6,115,442		16,196,587
Proceeds from the exercise of stock options	2,809		'
Proceeds from the exercise of warrants, net of issuance costs	460,097		4,153,584
Proceeds from loan payable, net of issuance costs	13,558,358		'
Payments related to net share issuance of stock based awards	-342,366		-59,090
Repayment of capital lease obligations	-7,302		-18,521
Repayment of bonds payable	-152,500		-141,250
Net cash provided by financing activities	19,634,538		20,131,310
Increase in cash and cash equivalents	12,486,485		2,413,838
Effects of foreign exchange rate changes on cash	-2,467		-12,411
Cash and cash equivalents, beginning of period	8,471,275		13,311,261
Cash and cash equivalents, end of period	20,955,293		15,712,688
Supplemental disclosure of cash flow information:	'		'
Interest paid	271,054		40,114
Supplemental schedule of non-cash investing and financing activities:	'		'
Fair value of 329,131 shares issued as consideration under an equity financing agreement	600,006	[1]	'
Stock issued for an option agreement	'		50,000	[2]
Equipment acquired under a capital lease	$43,600	[3]	$21,721	[3]
[1]	In June 2013, we entered into an agreement with an institutional investor, under which we have the right to sell up to $30.0 million of common stock to the institutional investor. In consideration for entering into the agreement, we issued 329,131 shares of our common stock to the institutional investor. We will not receive any cash proceeds from the issuance of these 329,131 shares. All shares sold or to be sold under this agreement are offered under our shelf registration statement previously filed with, and declared effective by, the SEC. In October 2013, we terminated the agreement without any cost or penalty.
[2]	In September 2012, we issued 24,753 shares of restricted common stock under the terms of an agreement with a developer of biological materials in return for certain product rights including an exclusive right of first offer to commercialize the developer's products as may be developed on or before April 18, 2017.
[3]	Represents the present value of future minimum capital lease payments for equipment leased.

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Cash Flows (Parenthetical) (USD $)	9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Statement Of Cash Flows [Abstract]	'	'
Shares issued as consideration under an equity financing agreement	329,131	'
Right to sell of common stock	$30	'
Restricted Common Stock issued to developer of biological material	'	24,753
Warrants termination agreement	'2013-10	'

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	Note 1. Summary of Significant Accounting Policies
	Nature of Business.
	StemCells, Inc., a Delaware corporation, is a biopharmaceutical company that operates in one segment, the research, development, and commercialization of stem cell therapeutics and related technologies.
	The accompanying financial data as of September 30, 2013 and for the three and nine months ended September 30, 2013 and 2012 have been prepared by us, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States (U.S. GAAP) have been condensed or omitted pursuant to these rules and regulations. The December 31, 2012 condensed consolidated balance sheet was derived from audited financial statements, but does not include all disclosures required by U.S. GAAP. However, we believe that the disclosures are adequate to make the information presented not misleading. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and the notes thereto included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2012.
	We have incurred significant operating losses since inception. We expect to incur additional operating losses over the foreseeable future. We have very limited liquidity and capital resources and must obtain significant additional capital and other resources in order to provide funding for our product development efforts, the acquisition of technologies, businesses and intellectual property rights, preclinical and clinical testing of our products, pursuit of regulatory approvals, acquisition of capital equipment, laboratory and office facilities, establishment of production capabilities, selling, general and administrative expenses and other working capital requirements. We rely on our cash reserves, proceeds from equity and debt offerings, credit facilities, proceeds from the transfer or sale of intellectual property rights, equipment, facilities or investments, government grants and funding from collaborative arrangements, to fund our operations. If we exhaust our cash reserves and are unable to obtain adequate financing, we may be unable to meet our operating obligations and we may be required to initiate bankruptcy proceedings. The financial statements do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the outcome of this uncertainty.
	Principles of Consolidation
	The condensed consolidated financial statements include the accounts of StemCells, Inc., and our wholly-owned subsidiaries, including StemCells California, Inc., Stem Cell Sciences Holdings Ltd, and Stem Cell Sciences (UK) Ltd. All significant intercompany accounts and transactions have been eliminated.
	Use of Estimates
	The preparation of financial statements in conformity with U.S. GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in our condensed consolidated financial statements and accompanying notes. Actual results could differ materially from these estimates.
	Significant estimates include the following:
		•		the grant date fair value of stock-based awards recognized as compensation expense (see Note 5, “Stock-Based Compensation”);
		•		the fair value of warrants recorded as a liability (see Note 9, “Warrant Liability”); and
		•		the fair value of goodwill and other intangible assets (see Note 4, “Goodwill and Other Intangible Assets”).
	Financial Instruments
	Cash and Cash Equivalents
	Cash equivalents are money market accounts, money market funds and investments with maturities of 90 days or less from the date of purchase.
	Marketable Securities
	Our existing marketable securities are designated as available-for-sale securities. These securities are carried at fair value (see Note 2, “Financial Instruments”), with the unrealized gains and losses reported as a component of stockholders’ equity. Management determines the appropriate designation of its investments (current or non-current) in marketable securities at the time of purchase and reevaluates such designation as of each balance sheet date. The cost of securities sold is based upon the specific identification method.
	If the estimated fair value of a security is below its carrying value, we evaluate whether we have the intent and ability to retain our investment for a period of time sufficient to allow for any anticipated recovery to the cost of the investment, and whether evidence indicating that the cost of the investment is recoverable within a reasonable period of time outweighs evidence to the contrary. Other-than-temporary declines in estimated fair value of all marketable securities are charged to “Other income (expense), net” in the accompanying condensed consolidated statements of operations. No such impairment was recognized during the three and nine months ended September 30, 2013 or 2012.
	Trade and Other Receivables
	Our receivables generally consist of interest income on our financial instruments, revenue from licensing agreements and grants, and revenue from product sales.
	Warrant Liability
	We account for our warrants in accordance with U.S. GAAP which defines how freestanding contracts that are indexed to and potentially settled in a company’s own stock should be measured and classified. Authoritative accounting guidance prescribes that only warrants issued by us under contracts that cannot be net-cash settled, and are both indexed to and settled in our common stock, can be classified as equity. As part of both our November 2008 and November 2009 financings, we issued warrants with five year terms to purchase 1,034,483 and 400,000 shares of our common stock at $23.00 and $15.00 per share, respectively. As part of our December 2011 financing, we issued Series A Warrants with a five year term to purchase 8,000,000 shares at $1.40 per share and Series B Warrants with a ninety trading day term to purchase 8,000,000 units at $1.25 per unit. Each unit underlying the Series B Warrants consisted of one share of our common stock and one Series A Warrant. In the first and second quarter of 2012, an aggregate of 2,700,000 Series B Warrants were exercised. For the exercise of these warrants, we issued 2,700,000 shares of our common stock and 2,700,000 Series A Warrants. The remaining 5,300,000 Series B Warrants expired unexercised by their terms on May 2, 2012. As terms of the warrants issued in 2008 and 2009, as well as the Series A and Series B Warrants, do not meet the specific conditions for equity classification, we are required to classify the fair value of these warrants as a liability, with subsequent changes in fair value to be recorded as income (loss) due to change in fair value of warrant liability. The fair value of the warrants issued in the 2008 and 2009 financings is determined using the Black-Scholes-Merton (Black-Scholes) option pricing model and the fair value of the Series A and Series B Warrants is determined using a Monte Carlo simulation model (see Note 9, “Warrant Liability”). The fair value is affected by changes in inputs to these models including our stock price, expected stock price volatility, the contractual term, and the risk-free interest rate. The use of a Monte Carlo simulation model requires input of additional assumptions including the progress of our R&D programs and its affect on potential future financings. We will continue to classify the fair value of the warrants as a liability until the warrants are exercised, expire or are amended in a way that would no longer require these warrants to be classified as a liability. The estimated fair value of our warrant liability at September 30, 2013, was approximately $8,421,000.
	Goodwill and Other Intangible Assets
	Goodwill and intangible assets deemed to have indefinite lives are not amortized but are subject to annual impairment tests. If the assumptions and estimates used to allocate the purchase price are not correct, or if business conditions change, purchase price adjustments or future asset impairment charges could be required. We test goodwill for impairment on an annual basis or more frequently if we believe indicators of impairment exist. Impairment evaluations involve management estimates of asset useful lives and future cash flows. Significant management judgment is required in the forecasts of future operating results that are used in the evaluations, and it is possible, even likely, that the plans and estimates used may be incorrect. If our actual results, or the plans and estimates used in future impairment analysis are lower than the original estimates used to assess the recoverability of these assets, we could incur additional impairment charges in a future period. We completed our annual impairment testing during the fourth quarter of 2012, and determined that there was no impairment of goodwill.
	Prior to fiscal year 2001, we capitalized certain patent costs, which are being amortized over the estimated life of the patent and would be expensed at the time such patents are deemed to have no continuing value. Since 2001, all patent costs are expensed as incurred. License costs are capitalized and amortized over the estimated life of the related license agreement.
	Revenue Recognition
	We currently recognize revenue resulting from the licensing and use of our technology and intellectual property, from government grants, from services provided to third parties, and from product sales. Licensing agreements may contain multiple elements, such as upfront fees, payments related to the achievement of particular milestones and royalties. Revenue from upfront fees for licensing agreements that contain multiple elements are generally deferred and recognized on a straight-line basis over the term of the agreement. Fees associated with substantive at risk performance-based milestones are recognized as revenue upon completion of the scientific or regulatory event specified in the agreement, and royalties received are recognized as earned. Revenue from licensing agreements is recognized net of a fixed percentage due to licensors as royalties. Grant revenue from government agencies are funds received to cover specific expenses and are recognized as earned upon either the incurring of reimbursable expenses directly related to the particular research plan or the completion of certain development milestones as defined within the terms of the relevant collaborative agreement or grant. Revenue from services to third parties is recognized when we have provided the agreed upon services. Revenue from product sales are recognized when the product is shipped and the order fulfilled.
	Stock-Based Compensation
	Compensation expense for stock-based payment awards to employees is based on their grant date fair value as calculated and amortized over their vesting period. See Note 5, “Stock-Based Compensation” for further information.
	We use the Black-Scholes model to calculate the fair value of stock-based awards.
	Per Share Data
	Basic net income or loss per share is computed by dividing net income or loss by the weighted average number of shares of common stock outstanding during the period. Diluted net income or loss per share is computed based on the weighted average number of shares of common stock and other dilutive securities. To the extent these securities are anti-dilutive, they are excluded from the calculation of diluted earnings per share.
	The following is a reconciliation of the numerators and denominators of the basic and diluted net loss per share computations:
			Three months ended September 30,						Nine months ended September 30,
			2013			2012			2013			2012
	Net loss		$	(7,191,653	)	$	(16,336,790	)	$	(19,476,782	)	$	(25,732,707	)
	Weighted average shares outstanding used to compute basic and diluted net income or loss per share			41,402,717			30,168,475			39,787,527			25,992,764
	Basic and diluted net loss per share		$	(0.17	)	$	(0.54	)	$	(0.49	)	$	(0.99	)
	The following outstanding potentially dilutive securities were excluded from the computation of diluted net income or loss per share because the effect would have been anti-dilutive as of September 30:
			2013			2012
	Options			431,558			474,917
	Restricted stock units			3,336,282			1,516,199
	Warrants			9,894,909			10,689,083
	Total			13,662,749			12,680,199
	Comprehensive Income (Loss)
	Comprehensive income (loss) is comprised of net income or loss and other comprehensive income or loss (OCL). OCL includes certain changes in stockholders’ equity that are excluded from net income or loss. Specifically, we include in OCL changes in unrealized gains and losses on our marketable securities and unrealized gains and losses on foreign currency translations. Accumulated other comprehensive income was $170,605, as of September 30, 2013, and accumulated other comprehensive income was $193,177, as of December 31, 2012.

Financial_Instruments

Financial Instruments	9 Months Ended
	Sep. 30, 2013
Investments Debt And Equity Securities [Abstract]	'
Financial Instruments	'
	Note 2. Financial Instruments
	The following table summarizes the fair value of our cash, cash equivalents and available-for-sale marketable securities held in our current investment portfolio:
		Amortized		Gross			Fair Value
		Cost		Unrealized
				(Losses)
	September 30, 2013
	Cash	$	377,695	$	—		$	377,695
	Cash equivalents		20,577,598		—			20,577,598
	Total cash, cash equivalents, and marketable securities	$	20,955,293	$	—		$	20,955,293
	December 31, 2012
	Cash	$	254,267	$	—		$	254,267
	Cash equivalents		8,217,259		(252	)		8,217,007
	Marketable debt securities, current		13,901,782		(1,104	)		13,900,678
	Total cash, cash equivalents, and marketable securities	$	22,373,308	$	(1,356	)	$	22,371,952
	At September 30, 2013, our investments in money market accounts are through a money market fund that invests in high quality, short-term money market instruments which are classified as cash equivalents in the accompanying Consolidated Balance Sheet due to their short maturities. The investment seeks to provide the highest possible level of current income while still maintaining liquidity and preserving capital. From time to time, we carry cash balances in excess of federally insured limits. Our cash balance at September 30, 2013 includes approximately $114,000 held by our U.K. subsidiary.

Fair_Value_Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurement	'
	Note 3. Fair Value Measurement
	Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. As a basis for considering such assumptions, we are required to apply a three-tier value hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value. The three levels of the fair value hierarchy are:
	Level 1 — Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets.
	Level 2 — Directly or indirectly observable inputs other than in Level 1, that include quoted prices for similar assets or liabilities in active markets or quoted prices for identical or similar assets or liabilities in markets that are not active.
	Level 3 — Unobservable inputs which are supported by little or no market activity that reflects the reporting entity’s own assumptions about the assumptions that market participants would use in pricing the asset or liability.
	The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Assets measured at fair value are classified below based on the three fair value hierarchy tiers described above.
	Our cash equivalents are classified as Level 1 because they are valued primarily using quoted market prices.
	Our bonds payable, marketable securities, and liability for warrants issued in our 2008 and 2009 financing, are classified as Level 2 as they are valued using alternative pricing sources and models utilizing market observable inputs.
	We estimated the fair value of our loan payable using the net present value of the payments discounted at an effective interest rate. We believe the estimates used to measure the fair value of our loan payable constitute Level 3 inputs.
	Our liability for warrants issued in our 2011 financing is classified as Level 3 as the liability is valued using a Monte Carlo simulation model. Some of the significant inputs used to calculate the fair value of warrant liability include our stock price on the valuation date, expected volatility of our common stock as traded on NASDAQ, and risk-free interest rates that are derived from the yield on U.S. Treasury debt securities, all of which are observable from active markets. However, the use of a Monte Carlo simulation model requires the input of additional subjective assumptions including management’s assumptions regarding the likelihood of a re-pricing of these warrants pursuant to anti-dilution provisions and the progress of our R&D programs and its affect on potential future financings.
	The following table presents financial assets and liabilities measured at fair value as of September 30, 2013:
		Fair Value Measurement
		at Report Date Using
		Quoted Prices			Significant			Unobservable			As of
		in Active Markets			Other			Inputs			September 30,
		for			Observable			(Level 3)			2013
		Identical Assets			Inputs
		(Level 1)			(Level 2)
	Financial assets:
	Cash equivalents:
	Money market funds	$	377,695		$	—		$	—		$	377,695
	U.S. Treasury debt obligations		20,577,598			—			—			20,577,598
	Total financial assets	$	20,955,293		$	—		$	—		$	20,955,293
	Financial liabilities:
	Bond obligation	$	—		$	178,750		$	—		$	178,750
	Loan payable net of discounts		—			—			13,468,348			13,468,348
	Warrant liabilities		—			15,260			8,405,694			8,420,954
	Total financial liabilities	$	—		$	194,010		$	21,874,042		$	22,068,052
	Level 2 Reconciliation
	The following table presents a roll forward for financial assets and liabilities measured at fair value using significant other observable inputs (Level 2) for 2013:
		Level 2			Net transfers (to)			Change			Settled			Level 2
		Beginning			from			included in			$			Ending
		Balance 12/31/12			Level 1			earnings						Balance 09/30/13
		$			$			$						$
	Marketable securities		13,900,678			(13,900,678	)		—			—			—
	Bond obligation		331,250			—			—			(152,500	)		178,750
	Warrant liabilities		107,968			—			(92,708	)		—			15,260
	Transfers from Level 2 to Level 1 are maturities of short term marketable debt securities into cash and cash equivalents.
	Level 3 Reconciliation
	The following table presents a roll forward for liabilities measured at fair value using significant unobservable inputs (Level 3) for 2013.
		Warrant
		Liabilities
	Balance at December 31, 2012	$	9,157,397
	Less fair value of warrants exercised		(418,841	)
	Add change in fair value of warrants		(332,862	)
	Balance at September 30, 2013	$	8,405,694
		Loan payable net of discounts
	Loan proceeds	$	13,820,264
	Less discount		(487,576	)
	Add amortization of discount		135,660
	Balance at September 30, 2013	$	13,468,348

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	9 Months Ended
	Sep. 30, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'
Goodwill and Other Intangible Assets	'
	Note 4. Goodwill and Other Intangible Assets
	On April 1, 2009, we acquired the operations of Stem Cell Sciences Plc (SCS) for an aggregate purchase price of approximately $5,135,000. The acquired operations includes proprietary cell technologies relating to embryonic stem cells, induced pluripotent stem (iPS) cells, and tissue-derived (adult) stem cells; expertise and infrastructure for providing cell-based assays for drug discovery; a cell culture products business; and an intellectual property portfolio with claims relevant to cell processing, reprogramming and manipulation, as well as to gene targeting and insertion.
	The purchase price was allocated as follows:
		Allocated purchase			Estimated life of
		Price			intangible assets
					in years
	Net tangible assets	$	36,000
	Intangible assets:
	Customer relationships and developed technology		1,310,000			6 to 9
	In-process research and development		1,340,000			N/A
	Trade name		310,000			15
	Goodwill		2,139,000			N/A
	Total	$	5,135,000
	In-process research and development assets relate to: 1) the acquisition of certain intellectual property rights not expected to expire until 2027 related to our program focused on developing genetically engineered rat models of human disease (our “Transgenic Rat Program”); and 2) the acquisition of certain technology related to the commercialization of our SC Proven cell culture products and the development and commercialization of cell-based assay platforms for use in drug discovery and development (our “Assay Development Program”).
	At the time of valuation (April 2009), our Transgenic Rat Program was in its nascent stage and our Assay Development Program was expected to achieve proof of concept by 2012. Neither program was expected to begin generating revenue until 2011-2012. In December 2011, in part because of management’s decision to focus on our therapeutic product development programs and not to allocate time and resources to the assays technology, we determined that we could not predict the future cash flows from the intangible IPR&D asset related to the Assay Development Program. Therefore, at December 31, 2011, we determined that the intangible asset was impaired and wrote off the approximately $655,000 carrying value of the asset.
	Trade name relates to the “SC Proven” trademark of our cell culture products which we expect to market for 15 years from the date of acquisition, based on which, we estimated a remaining useful life of 15 years from the valuation date.
	The following table presents changes in goodwill:
	Balance as of December 31, 2012	$	1,983,426
	Foreign currency translation		(10,124	)
	Balance as of September 30, 2013	$	1,973,302
	The components of our other intangible assets at September 30, 2013 are summarized below:
	Other Intangible Asset Class	Cost			Additions		Impairment			Accumulated			Foreign Currency		Net Carrying		Weighted-
										Amortization			Translation		Amount		Average
																	Amortization
																	Period
	Customer relationships and developed technology	$	1,310,000		$	—	$	—		$	(829,204	)	$	142,683	$	623,479		8.0 years
	In-process research and development		1,340,000			—		(654,961	)		(270,687	)		133,300		547,652		Indefinite
	Trade name		310,000			—		—			(102,118	)		35,913		243,795		15.0 years
	Patents		979,612			64,000		—			(785,487	)		—		258,125		16.0 years
	Total other intangible assets	$	3,939,612		$	64,000	$	(654,961	)	$	(1,987,496	)	$	311,896	$	1,673,051		12.2 years
	Amortization expense was approximately $66,000 in the third quarter of 2013.
	The expected future annual amortization expense for each of the next five years based on current balances of our intangible assets is approximately as follows:
	For the year ending December 31:
	2013	$	289,000
	2014	$	275,000
	2015	$	275,000
	2016	$	267,000
	2017	$	247,000

StockBased_Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock-Based Compensation	'
	Note 5. Stock-Based Compensation
	We currently grant stock-based compensation under two equity incentive plans approved by the Company’s stockholders and one plan adopted in 2012 pursuant to NASDAQ Listing Rule 5635(c)(4) concerning inducement grants for new employees (our “2012 Commencement Incentive Plan”). As of September 30, 2013, we had 2,601,389 shares available to grant under the above mentioned plans. At our annual stockholders meeting held on June 12, 2007, our stockholders approved an amendment to our 2006 Equity Incentive Plan to provide for an annual increase in the number of shares of common stock available for issuance under the plan each January 1 (beginning January 1, 2008) equal to 4% of the outstanding common shares as of that date. The amendment further provided an aggregate limit of 3,000,000 shares issuable pursuant to incentive stock option awards under the plan. Under the two stockholder-approved plans we may grant incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock, restricted stock units, 401(k) Plan employer match in form of shares and performance-based shares to our employees, directors and consultants, at prices determined by our Board of Directors. Incentive stock options may only be granted to employees under these plans with a grant price not less than the fair market value on the date of grant. Under our 2012 Commencement Inducement Plan, we may only award options, restricted stock units and other equity awards to newly hired employees and newly engaged directors, in each case as allowed by NASDAQ listing requirements.
	Our stock-based compensation expense for the three and nine months ended September 30 was as follows:
			Three months ended						Nine months ended
			September 30,						September 30,
			2013			2012			2013			2012
	Research and development expense		$	346,938		$	314,393		$	1,064,301		$	966,570
	Selling, general and administrative expense			250,067			452,760			968,927			1,260,575
	Total stock-based compensation		$	597,005		$	767,153		$	2,033,228		$	2,227,145
	Effect on basic and diluted net loss per share		$	(0.01	)	$	(0.03	)	$	(0.05	)	$	(0.09	)
	As of September 30, 2013, we had approximately $4,767,000 of total unrecognized compensation expense related to unvested awards of stock options and restricted stock units granted under our various equity incentive plans that we expect to recognize over a weighted-average vesting period of 3.2 years.
	Stock Options
	Generally, stock options granted to employees have a maximum term of ten years, and vest over a four year period from the date of grant; 25% vest at the end of one year, and 75% vest monthly over the remaining three-year service period. We may grant options with different vesting terms from time to time. Upon employee termination of service, any unexercised vested option will be forfeited three months following termination or the expiration of the option, whichever is earlier. Unvested options are forfeited on termination.
	A summary of our stock option activity for the three months ended September 30, 2013 is as follows:
			Number of options			Weighted-average
						exercise price ($) per share
	Balance at June 30, 2013			440,126			19.85
	Granted			—			—
	Exercised			(723	)		1
	Cancelled			(7,845	)		18.87
	Outstanding options at September 30, 2013			431,558			19.9
	A summary of changes in unvested options for the three months ended September 30, 2013 is as follows:
			Number of options			Weighted-average			Weighted-average
						exercise price ($) per share			grant
									date fair value ($) per option
	Unvested options at June 30, 2013			39,097			10.37			8.25
	Granted			—			—			—
	Vested			(10,374	)		10.55			8.38
	Cancelled			—			—			—
	Unvested options at September 30, 2013			28,723			10.31			8.2
	The estimated fair value of options vested was approximately $87,000 in the three months ended September 30, 2013.
	Restricted Stock Units
	We have granted restricted stock units (RSUs) to certain employees and members of the Board of Directors which entitle the holders to receive shares of our common stock upon vesting of the RSUs. The fair value of restricted stock units granted is based upon the market price of the underlying common stock as if it were vested and issued on the date of grant.
	A summary of changes in our restricted stock units for the three months ended September 30, 2013 is as follows:
			Number of RSUs			Weighted-average
						grant
						date fair value ($) per RSU
	Outstanding restricted stock units at June 30, 2013			3,350,616			1.7
	Granted(1)			60,000			1.73
	Vested and exercised			(30,334	)		3.26
	Cancelled			(44,000	)		2.01
	Outstanding restricted stock units at September 30, 2013			3,336,282			1.68
	-1	10,000 of these restricted stock units vest and convert into shares of our common stock after one year from the date of grant. 50,000 of these restricted stock units will vest and convert into shares of our common stock over a four year period from the date of grant; one-fourth of the award will vest on each grant date anniversary following the grant.
	Stock Appreciation Rights
	In July 2006, we granted cash-settled Stock Appreciation Rights (SARs) to certain employees that give the holder the right, upon exercise, to the difference between the price per share of our common stock at the time of exercise and the exercise price of the SARs.
	The SARs have a maximum term of ten years with an exercise price of $20.00, which is equal to the market price of our common stock at the date of grant. The SARs vest 25% on the first anniversary of the grant date and 75% vest monthly over the remaining three-year service period. All of the outstanding SARs as of September 30, 2013 are fully vested. Compensation expense is based on the fair value of SARs which is calculated using the Black-Scholes option pricing model.
	The stock-based compensation expense and liability are re-measured at each reporting date through the earlier of date of settlement or forfeiture of the SARs.
	A summary of the changes in SARs for the three months ended September 30, 2013 is as follows:
			Number of SARs
	Outstanding at June 30, 2013			110,593
	Granted			—
	Exercised			—
	Forfeited and expired			—
	Outstanding SARs at September 30, 2013			110,593
	SARs exercisable at September 30, 2013			110,593
	For the three months ended September 30, 2013 and 2012, the re-measured liability and expense for the respective periods related to the SARs were not significant.
	The compensation expense related to the SARs recognized for the three months ended September 30, 2013 may not be representative of compensation expense for future periods and its resulting effect on net loss and net loss per share attributable to common stockholders, due to changes in the fair value calculation which is dependent on the stock price, volatility, interest and forfeiture rates, additional grants and subsequent periods of vesting. We will continue to recognize compensation cost each period, which will be the change in fair value from the previous period through the earlier date of settlement or forfeiture of the SARs.

WindDown_Expenses

Wind-Down Expenses	9 Months Ended
	Sep. 30, 2013
Restructuring And Related Activities [Abstract]	'
Wind-Down Expenses	'
	Note 6. Wind-Down Expenses
	Rhode Island
	In connection with our wind-down of our research and manufacturing operations in Lincoln, Rhode Island, and the relocation of our corporate headquarters and remaining research laboratories to California in October 1999, we provided a reserve for our exit cost obligation. The reserve was for the estimated costs of our former research and administrative facility in Lincoln, which we held on a lease that terminated on June 30, 2013. We periodically re-evaluated and adjusted the reserve after considering various factors such as our lease payments through to the end of the lease, operating expenses, the real estate market in Rhode Island, and estimated subtenant income based on actual and projected occupancy. The reserve was approximately $505,000 at March 31, 2013. In the second quarter of 2013, payments net of subtenant income of approximately $505,000 were recorded against this reserve and approximately $39,000 as additional wind-down expenses. We have closed this reserve as the lease and our obligations related to it terminated on June 30, 2013.
	The summary of the changes to our wind-down reserve related to this facility for 2013 and 2012 were as follows:
		January 1 to			April 1 to			January 1 to			January 1 to
		March 31,			June 30,			June 30,			December 31,
		2013			2013			2013			2012
	Accrued wind-down reserve at beginning of period	$	854,000		$	505,000		$	854,000		$	1,683,000
	Less actual expenses recorded against estimated reserve during the period		(372,000	)		(505,000	)		(877,000	)		(1,185,000	)
	Additional expense recorded to revise estimated reserve at period-end		23,000			—			23,000			356,000
	Revised reserve at period-end		505,000			—			—			854,000
	Add deferred rent at period-end		124,000			—			—			249,000
	Total accrued wind-down expenses at period-end, current	$	629,000		$	—		$	—		$	1,103,000

Loan_Payable

Loan Payable	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Loan Payable	'
	Note 7. Loan Payable
	Loan Agreement with Silicon Valley Bank
	In April 2013, we entered into a Loan Agreement with Silicon Valley Bank (SVB) and received loan proceeds of $9,900,000, net of a $100,000 cash discount. The loan proceeds will be used for research and development and general corporate purposes. The loan has a three-year term and bears interest at an annual rate of 6%. The loan obligations are secured by a first priority security interest on substantially all of our assets excluding intellectual property. For the first six months, payments will be interest only followed by repayment of principal and interest over a period of 30 months. There is also a final $1,000,000 fee payable at the end of the term which is being expensed over the term of the loan using the effective interest method. In conjunction with the Loan Agreement, we issued to SVB a ten year warrant to acquire 293,531 shares of common stock at an exercise price of $1.7034 per share. The warrant is immediately exercisable and expires in April 2023. We estimated the fair value of the warrant to be approximately $388,000 using the Black-Scholes option pricing model with the following assumptions:
	Expected life (years)	10
	Risk-free interest rate	1.9	%
	Expected volatility	88.1	%
	Expected dividend yield	0	%
	We applied the relative fair value method to allocate the $9,900,000 net proceeds between the loan and warrant. The approximately $388,000 fair value allocated to the warrant was recorded as an increase to additional paid-in capital and as a discount to loan payable. Approximately $9,512,000 was assigned to the loan and was recorded as the initial carrying amount of the loan payable, net of discount. The approximately $388,000 fair value of the warrant and the $100,000 cash discount are both being amortized as additional interest expense over the term of the loan using the effective interest rate method.
	We also incurred loan issuance costs of approximately $117,000, which are recorded as deferred financing costs on the accompanying condensed consolidated balance sheet and are being amortized to interest expense over the term of the Loan Agreement using the effective interest rate method.
	The effective interest rate used to amortize the deferred financing costs and the discount (including the fair value of the warrant and the cash discount), and for the accretion of the final payment, is 9.0%.
	Loan Agreement with California Institute for Regenerative Medicine
	In April 2013, we entered into an agreement with the California Institute for Regenerative Medicine (CIRM) (the CIRM Loan Agreement) under which CIRM will provide up to approximately $19.3 million to help fund preclinical development and IND-enabling activities of our HuCNS-SC cells for Alzheimer’s disease. This funding was awarded in September 2012 under CIRM’s Disease Team Therapy Development Award program (RFA 10-05), and the goal of the research is to file an Investigational New Drug application with the U.S. Food and Drug Administration within four years. The funding is in the form of a forgivable loan, in accordance with mutually agreed upon terms and conditions and CIRM regulations, and is expected to be disbursed periodically by CIRM over the four-year project period subject to a number of preconditions, including the achievement of certain progress milestones and compliance with certain financial covenants. The loan is unsecured and the term of the loan is ten years and may be extended under certain circumstances. Initially, the loan will bear interest at the one year LIBOR rate plus two percent and will increase by 1% each year after year five. Interest will accrue with the first disbursement of loan funds, but we will not begin paying interest until year six. Repayment of the principal and any accrued and unpaid interest will be due and payable at the end of the term. We can prepay the CIRM loan at our election, either in whole or in part at any time and without a prepayment fee. In addition, the loan is forgivable so that our obligation to repay will be contingent upon the success of our HuCNS-SC cells as a treatment for Alzheimer’s disease. In July 2013, we received approximately $3.8 million as the initial disbursement of the loan provided under the CIRM Loan Agreement.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments And Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Note 8. Commitments and Contingencies
	Leases
	Capital Leases
	We entered into direct financing transactions with the State of Rhode Island and received proceeds from the issuance of industrial revenue bonds totaling $5,000,000 to finance the construction of our pilot manufacturing facility in Rhode Island. The related lease agreements are structured such that lease payments fully fund all semiannual interest payments and annual principal payments through maturity in August 2014. The interest rate for the remaining bond series is 9.5%. The bond contains certain restrictive covenants which limit, among other things, the payment of cash dividends and the sale of the related assets. The outstanding principal was approximately $179,000 at September 30, 2013 and $331,000 at December 31, 2012.
	Operating Leases
	We lease various real properties under operating leases that generally require us to pay taxes, insurance, maintenance, and minimum lease payments. Some of our leases have options to renew.
	Operating Leases — California
	In September 2010, we entered into a two-year sublease agreement with Caliper Life Sciences, Inc., for office and research space in a facility located in Mountain View, California. In June 2012, the sublease term was extended to and expired on September 30, 2013. We paid approximately $1,081,000 in aggregate as rent over the term of the lease.
	In December 2010, we entered into a commercial lease agreement with BMR-Gateway Boulevard LLC (BMR), as landlord, for office and research space at BMR’s Pacific Research Center in Newark, California. The initial term of the lease is approximately eleven and one-half years and includes escalating rent payments which we recognize as lease operating expense on a straight-line basis. We will pay approximately $17,869,000 in aggregate as rent over the term of the lease to BMR. Deferred rent for this facility was approximately $1,432,000 as of September 30, 2013, and approximately $1,389,000 as of December 31, 2012.
	In March 2013, we entered into a commercial lease agreement with Prologis, L.P. (Prologis), as landlord, for office and research space in Sunnyvale, California. The facility is for operations that support our clinical development activities. The initial term of the lease is ten years and includes escalating rent payments which we recognize as lease operating expense on a straight-line basis. We will pay approximately $3,497,000 in aggregate rent over the term of the lease. As part of the lease, Prologis has agreed to provide us financial allowances to build initial tenant improvements, subject to customary terms and conditions relating to landlord-funded tenant improvements. The tenant improvements are recorded as leasehold improvement assets and amortized over the term of the lease. The financial allowances are treated as a lease incentive and recorded as deferred rent which is amortized as reductions to lease expense over the lease term. Deferred rent for this facility was approximately $389,000 as of September 30, 2013.
	Operating Leases — Rhode Island
	We entered into a fifteen-year lease agreement for a scientific and administrative facility (SAF) in Rhode Island in connection with a sale and leaseback arrangement in 1997. The lease term expired on June 30, 2013. For the year 2013, we paid approximately $1,165,000 in operating lease payments and operating expenses net of sub-tenant income.
	Operating Leases — United Kingdom
	In January 2011, we amended the existing lease agreements of our wholly-owned subsidiary, Stem Cell Sciences (U.K.) Ltd, effectively reducing our leased office and lab space. The lease by its terms was extended to September 30, 2013. In October 2013, we signed a new three-year lease agreement for the leased space and expect to pay rent of approximately GBP 53,000 per annum. StemCells, Inc. is the guarantor of Stem Cell Sciences (U.K.) Ltd’s obligations under the existing lease.
	With the exception of the operating leases discussed above, we have not entered into any significant off balance sheet financial arrangements and have not established any special purpose entities. We have not guaranteed any debts or commitments of other entities or entered into any options on non-financial assets.
	Contingencies
	In July 2006, we filed suit against Neuralstem, Inc. in the Federal District Court for the District of Maryland, alleging that Neuralstem’s activities violate claims in four of the patents we exclusively licensed from NeuroSpheres Holdings Ltd. and NeuroSpheres Ltd. (NeuroSpheres), specifically U.S. Patent No. 6,294,346 (claiming the use of human neural stem cells for drug screening), U.S. Patent No. 7,101,709 (claiming the use of human neural stem cells for screening biological agents), U.S. Patent No. 5,851,832 (claiming methods for proliferating human neural stem cells), and U.S. Patent No. 6,497,872 (claiming methods for transplanting human neural stem cells). In May 2008, we filed a second patent infringement suit against Neuralstem and its two founders, Karl Johe and Richard Garr. In this suit, which we filed in the Federal District Court for the Northern District of California, we allege that Neuralstem’s activities infringe claims in two patents we exclusively license from NeuroSpheres, specifically U.S. Patent No. 7,361,505 (claiming composition of matter of human neural stem cells derived from any source material) and U.S. Patent No. 7,115,418 (claiming methods for proliferating human neural stem cells). In addition, we allege various state law causes of action against Neuralstem arising out of its repeated derogatory statements to the public about our patent portfolio. Also in May 2008, Neuralstem filed suit against us and NeuroSpheres in the Federal District Court for the District of Maryland seeking a declaratory judgment that the ‘505 and ‘418 patents are either invalid or are not infringed by Neuralstem and that Neuralstem has not violated California state law. In August 2008, the California court transferred our lawsuit against Neuralstem to Maryland for resolution on the merits. In July 2009, the Maryland District Court granted our motion to consolidate these two cases with the litigation we initiated against Neuralstem in 2006. Discovery is ongoing in these cases and we anticipate a trial date in 2014.
	In October, 2013, we acquired from NeuroSpheres a patent portfolio consisting of the patents we licensed from NeuroSpheres on an exclusive worldwide basis, including the six patents that are the subject of our patent infringement litigation against Neuralstem. As consideration for the patents, we will issue 139,548 shares of unregistered common stock to NeuroSpheres. In connection with the patent acquisition, all preexisting agreements were terminated. The acquisition relieves us from further milestone and royalty payments to NeuroSpheres.

Warrant_Liability

Warrant Liability	9 Months Ended
	Sep. 30, 2013
Text Block [Abstract]	'
Warrant Liability	'
	Note 9. Warrant Liability
	We use various option pricing models, such as the Black-Scholes option pricing model and a Monte Carlo simulation model, to estimate fair value of warrants issued. In using these models, we make certain assumptions about risk-free interest rates, dividend yields, volatility, expected term of the warrants and other assumptions. Risk-free interest rates are derived from the yield on U.S. Treasury debt securities. Dividend yields are based on our historical dividend payments, which have been zero to date. Volatility is estimated from the historical volatility of our common stock as traded on NASDAQ. The expected term of the warrants is based on the time to expiration of the warrants from the date of measurement.
	In November 2008, we sold 1,379,310 units to institutional investors at a price of $14.50 per unit, for gross proceeds of $20,000,000. The units, each of which consisted of one share of common stock and a warrant to purchase 0.75 shares of common stock at an exercise price of $23.00 per share, were offered as a registered direct offering under a shelf registration statement previously filed with, and declared effective by, the SEC. We received total proceeds, net of offering expenses and placement agency fees, of approximately $18,637,000. We recorded the fair value of the warrants to purchase 1,034,483 shares of our common stock as a liability. The fair value of the warrant liability is revalued at the end of each reporting period, with the change in fair value of the warrant liability recorded as a gain or loss in our condensed consolidated statements of operations. The fair value of the warrants will continue to be classified as a liability until such time as the warrants are exercised, expire or an amendment of the warrant agreement renders these warrants to be no longer classified as a liability.
	The assumptions used for the Black-Scholes option pricing model are as follows:
		To Calculate
		Fair Value of Warrant
		Liability at
		September 30, 2013			December 31, 2012
	Expected life (years)		0.6			1.4
	Risk-free interest rate		0.1	%		0.2	%
	Expected volatility		40.2	%		108.2	%
	Expected dividend yield		0	%		0	%
		At September 30,			At December 31,			Change in Fair Value
		2013			2012			of Warrant Liability
	Fair value of liability for warrants issued in 2008	$	0		$	44,628		$	(44,628	)
	In November 2009, we sold 1,000,000 units to institutional investors at a price of $12.50 per unit, for gross proceeds of $12,500,000. The units, each of which consisted of one share of common stock and a warrant to purchase 0.40 shares of common stock at an exercise price of $15.00 per share, were offered as a registered direct offering under a shelf registration statement previously filed with, and declared effective by, the SEC. We received total proceeds, net of offering expenses and placement agency fees, of approximately $11,985,000. We recorded the fair value of the warrants to purchase 400,000 shares of our common stock as a liability. The fair value of the warrant liability is revalued at the end of each reporting period, with the change in fair value of the warrant liability recorded as a gain or loss in our condensed consolidated statements of operations. The fair value of the warrants will continue to be classified as a liability until such time as the warrants are exercised, expire or an amendment of the warrant agreement renders these warrants to be no longer classified as a liability.
	The assumptions used for the Black-Scholes option pricing model are as follows:
		To Calculate
		Fair Value of Warrant Liability at
		September 30,			December 31,
		2013			2012
	Expected life (years)		1.6			2.3
	Risk-free interest rate		0.3	%		0.3	%
	Expected volatility		86.1	%		94.5	%
	Expected dividend yield		0	%		0	%
		At September 30,			At December 31,			Change in Fair Value
		2013			2012			of Warrant Liability
	Fair value of liability for warrants issued in 2009	$	15,260		$	63,340		$	(48,080	)
	In December 2011, we raised gross proceeds of $10,000,000 through a public offering of 8,000,000 units and 8,000,000 Series B Warrants. The combination of units and Series B Warrants were sold at a public offering price of $1.25 per unit. Each Series B Warrant gave the holder the right to purchase one unit at an exercise price of $1.25 per unit and was exercisable until May 2, 2012, the 90th trading day after the date of issuance. Each unit consists of one share of our common stock and one Series A Warrant. Each Series A Warrant gives the holder the right to purchase one share of our common stock at an initial exercise price of $1.40 per share. The Series A Warrants are immediately exercisable upon issuance and will expire in December 2016. In 2012, an aggregate of 2,700,000 Series B Warrants were exercised. For the exercise of these warrants, we issued 2,700,000 shares of our common stock and 2,700,000 Series A Warrants. The remaining 5,300,000 Series B Warrants expired unexercised by their terms on May 2, 2012. In 2012, an aggregate of 2,198,571 Series A Warrants were exercised. For the exercise of these warrants, we issued 2,198,571 shares of our common stock. In the first quarter of 2013, an aggregate of 334,534 Series A Warrants were exercised. For the exercise of these warrants, we issued 334,534 shares of our common stock and received gross proceeds of approximately $468,000. The shares were offered under our shelf registration statement previously filed with previously filed with, and declared effective by, the SEC.
	The assumptions used for the Monte Carlo simulation model to value the Series A Warrants at September 30, 2013 are as follows:
	Risk-free interest rate per year		0.7	%
	Expected volatility per year		83.6	%
	Expected dividend yield		0	%
	Expected life in years		3.2
	The use of a Monte Carlo simulation model requires the input of additional subjective assumptions including the progress of our R&D programs and its affect on potential future financings.
	The following table is a summary of the changes in fair value of warrant liability for the Series A Warrants for the nine-month period ended September 30, 2013:
		Series A
		Number of			Fair value $
		Warrants
	Balance at December 31, 2012		8,501,429		$	9,157,397
	Less exercised		(334,534	)		(418,841	)
	Changes in fair value		—			(332,862	)
	Balance at September 30, 2013		8,166,895		$	8,405,694
	The following table is a summary of our warrant liability as of September 30, 2013:
	Warrants	Number Outstanding			Exercise Price ($)			Fair value
					per share
	Warrants issued in 2008		1,034,483			23		$	—
	Warrants issued in 2009		400,000			15			15,260
	Series A Warrants		8,166,895			1.4			8,405,694
	Total		9,601,378					$	8,420,954
	The fair value of the warrant liability is revalued at the end of each reporting period, with the change in fair value of the warrant liability recorded as a gain or loss in our condensed consolidated statements of operations. The fair value of the warrants will continue to be classified as a liability until such time as the warrants are exercised, expire or an amendment of the warrant agreement renders these warrants to be no longer classified as a liability.

Common_Stock

Common Stock	9 Months Ended
	Sep. 30, 2013
Equity [Abstract]	'
Common Stock	'
	Note 10. Common Stock
	In June 2009, we entered into a sales agreement (2009 sales agreement) pursuant to which we had the option to sell up to $30 million of our common stock, from time to time, in at-the-market offerings. Between June 2009 and November 2012, we sold common stock under the 2009 sales agreement worth approximately $26.7 million. In December 2012, we amended the 2009 sales agreement (2012 amended sales agreement) to, among other provisions, raise the dollar amount of shares available to sell under the agreement back to $30 million. The sales agent is paid compensation of up to 3% of gross proceeds pursuant to the terms of the agreement. The sales agreement, as amended, has been filed with the SEC. During the nine-month period ended September 30, 2013, we sold a total of 1,733,771 shares of our common stock at an average price per share of $1.91 for gross proceeds of approximately $3,317,000. The shares were sold under the 2012 amended sales agreement. The shares were offered under our shelf registration statement previously filed with, and declared effective by, the SEC.
	In the first quarter of 2013, an aggregate of 334,534 Series A Warrants were exercised. For the exercise of these warrants, we issued 334,534 shares of our common stock and received gross proceeds of approximately $468,000.
	In June 2013, we entered into an agreement with an institutional investor, under which we have the right to sell up to $30.0 million of our common stock to the institutional investor. Proceeds from the sale of our common stock will be used for general corporate purposes. Under the terms of the agreement, we immediately sold 1,645,639 in shares of our common stock to the institutional investor at a purchase price of $1.823 per share, which was the volume-weighted average price of the prior ten trading days, and received gross proceeds of $3.0 million. In consideration for entering into the agreement, we issued 329,131 shares of our common stock to the institutional investor. We did not receive any cash proceeds from the issuance of these 329,131 shares. Under this agreement, we have the right for a period of three years and at our sole discretion, to sell additional amounts up to $27.0 million of our common stock to the institutional investor subject to certain limitations. No warrants were issued in connection with this transaction. All shares were sold under our shelf registration statement previously filed with, and declared effective by, the SEC. In October 2013, we terminated the agreement without any cost or penalty.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	9 Months Ended
	Sep. 30, 2013
Text Block [Abstract]	'
Accumulated Other Comprehensive Income	'
	Note 11. Accumulated Other Comprehensive Income
	The following table sets forth the changes in accumulated other comprehensive loss by component for the three months ended September 30, 2013:
		Unrealized Gain			Foreign Currency			Total
		on Other			Translation
		Available-for-Sale
		Securities
	Beginning balance	$	425		$	(35,515	)	$	(35,090	)
	Other comprehensive income before reclassifications		(425	)		206,121			205,696
	Amounts reclassified from accumulated other comprehensive loss		—			—			—
	Net current-period other comprehensive income (loss)		(425	)		206,121			205,696
	Ending balance	$	—		$	170,606		$	170,606

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 30, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
	Note 12. Subsequent Events
	In October 2013, we sold a total of 12,845,500 units in an underwritten public offering at a price of $1.45 per unit and received total proceeds, net of offering expenses, underwriting discounts and commissions, of approximately $17.3 million. Each unit sold consisted of one share of common stock, par value $.01 per share, and a warrant to purchase one-half share of common stock. The warrants have an exercise price of $1.80 per share, are exercisable immediately, and will expire five years from the date of issuance.
	Subsequent to the end of the third quarter, 50,000 Series A Warrants were exercised at an exercise price of $1.40 per share. We will receive gross proceeds of approximately $70,000 and issue 50,000 shares of our common stock.
	In October, 2013, we acquired from NeuroSpheres a patent portfolio we licensed on an exclusive worldwide basis, including the six patents that are the subject of our patent infringement litigation against Neuralstem. As consideration for the patents, we will issue 139,548 shares of unregistered common stock to NeuroSpheres. In connection with the patent acquisition, all preexisting agreements were terminated. The acquisition relieves us from further milestone and royalty payments to NeuroSpheres.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2013

Accounting Policies [Abstract]

'

Nature of Business

'

Nature of Business.

StemCells, Inc., a Delaware corporation, is a biopharmaceutical company that operates in one segment, the research, development, and commercialization of stem cell therapeutics and related technologies.

The accompanying financial data as of September 30, 2013 and for the three and nine months ended September 30, 2013 and 2012 have been prepared by us, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States (U.S. GAAP) have been condensed or omitted pursuant to these rules and regulations. The December 31, 2012 condensed consolidated balance sheet was derived from audited financial statements, but does not include all disclosures required by U.S. GAAP. However, we believe that the disclosures are adequate to make the information presented not misleading. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and the notes thereto included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2012.

We have incurred significant operating losses since inception. We expect to incur additional operating losses over the foreseeable future. We have very limited liquidity and capital resources and must obtain significant additional capital and other resources in order to provide funding for our product development efforts, the acquisition of technologies, businesses and intellectual property rights, preclinical and clinical testing of our products, pursuit of regulatory approvals, acquisition of capital equipment, laboratory and office facilities, establishment of production capabilities, selling, general and administrative expenses and other working capital requirements. We rely on our cash reserves, proceeds from equity and debt offerings, credit facilities, proceeds from the transfer or sale of intellectual property rights, equipment, facilities or investments, government grants and funding from collaborative arrangements, to fund our operations. If we exhaust our cash reserves and are unable to obtain adequate financing, we may be unable to meet our operating obligations and we may be required to initiate bankruptcy proceedings. The financial statements do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from the outcome of this uncertainty.

Principles of Consolidation

'

Principles of Consolidation

The condensed consolidated financial statements include the accounts of StemCells, Inc., and our wholly-owned subsidiaries, including StemCells California, Inc., Stem Cell Sciences Holdings Ltd, and Stem Cell Sciences (UK) Ltd. All significant intercompany accounts and transactions have been eliminated.

Use of Estimates

'

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make judgments, assumptions and estimates that affect the amounts reported in our condensed consolidated financial statements and accompanying notes. Actual results could differ materially from these estimates.

Significant estimates include the following:

•

the grant date fair value of stock-based awards recognized as compensation expense (see Note 5, “Stock-Based Compensation”);

•

the fair value of warrants recorded as a liability (see Note 9, “Warrant Liability”); and

•

the fair value of goodwill and other intangible assets (see Note 4, “Goodwill and Other Intangible Assets”).

Financial Instruments

'

Financial Instruments

Cash and Cash Equivalents

Cash equivalents are money market accounts, money market funds and investments with maturities of 90 days or less from the date of purchase.

Marketable Securities

Our existing marketable securities are designated as available-for-sale securities. These securities are carried at fair value (see Note 2, “Financial Instruments”), with the unrealized gains and losses reported as a component of stockholders’ equity. Management determines the appropriate designation of its investments (current or non-current) in marketable securities at the time of purchase and reevaluates such designation as of each balance sheet date. The cost of securities sold is based upon the specific identification method.

If the estimated fair value of a security is below its carrying value, we evaluate whether we have the intent and ability to retain our investment for a period of time sufficient to allow for any anticipated recovery to the cost of the investment, and whether evidence indicating that the cost of the investment is recoverable within a reasonable period of time outweighs evidence to the contrary. Other-than-temporary declines in estimated fair value of all marketable securities are charged to “Other income (expense), net” in the accompanying condensed consolidated statements of operations. No such impairment was recognized during the three and nine months ended September 30, 2013 or 2012.

Trade and Other Receivables

Our receivables generally consist of interest income on our financial instruments, revenue from licensing agreements and grants, and revenue from product sales.

Warrant Liability

We account for our warrants in accordance with U.S. GAAP which defines how freestanding contracts that are indexed to and potentially settled in a company’s own stock should be measured and classified. Authoritative accounting guidance prescribes that only warrants issued by us under contracts that cannot be net-cash settled, and are both indexed to and settled in our common stock, can be classified as equity. As part of both our November 2008 and November 2009 financings, we issued warrants with five year terms to purchase 1,034,483 and 400,000 shares of our common stock at $23.00 and $15.00 per share, respectively. As part of our December 2011 financing, we issued Series A Warrants with a five year term to purchase 8,000,000 shares at $1.40 per share and Series B Warrants with a ninety trading day term to purchase 8,000,000 units at $1.25 per unit. Each unit underlying the Series B Warrants consisted of one share of our common stock and one Series A Warrant. In the first and second quarter of 2012, an aggregate of 2,700,000 Series B Warrants were exercised. For the exercise of these warrants, we issued 2,700,000 shares of our common stock and 2,700,000 Series A Warrants. The remaining 5,300,000 Series B Warrants expired unexercised by their terms on May 2, 2012. As terms of the warrants issued in 2008 and 2009, as well as the Series A and Series B Warrants, do not meet the specific conditions for equity classification, we are required to classify the fair value of these warrants as a liability, with subsequent changes in fair value to be recorded as income (loss) due to change in fair value of warrant liability. The fair value of the warrants issued in the 2008 and 2009 financings is determined using the Black-Scholes-Merton (Black-Scholes) option pricing model and the fair value of the Series A and Series B Warrants is determined using a Monte Carlo simulation model (see Note 9, “Warrant Liability”). The fair value is affected by changes in inputs to these models including our stock price, expected stock price volatility, the contractual term, and the risk-free interest rate. The use of a Monte Carlo simulation model requires input of additional assumptions including the progress of our R&D programs and its affect on potential future financings. We will continue to classify the fair value of the warrants as a liability until the warrants are exercised, expire or are amended in a way that would no longer require these warrants to be classified as a liability. The estimated fair value of our warrant liability at September 30, 2013, was approximately $8,421,000.

Goodwill and Other Intangible Assets

'

Goodwill and Other Intangible Assets

Goodwill and intangible assets deemed to have indefinite lives are not amortized but are subject to annual impairment tests. If the assumptions and estimates used to allocate the purchase price are not correct, or if business conditions change, purchase price adjustments or future asset impairment charges could be required. We test goodwill for impairment on an annual basis or more frequently if we believe indicators of impairment exist. Impairment evaluations involve management estimates of asset useful lives and future cash flows. Significant management judgment is required in the forecasts of future operating results that are used in the evaluations, and it is possible, even likely, that the plans and estimates used may be incorrect. If our actual results, or the plans and estimates used in future impairment analysis are lower than the original estimates used to assess the recoverability of these assets, we could incur additional impairment charges in a future period. We completed our annual impairment testing during the fourth quarter of 2012, and determined that there was no impairment of goodwill.

Prior to fiscal year 2001, we capitalized certain patent costs, which are being amortized over the estimated life of the patent and would be expensed at the time such patents are deemed to have no continuing value. Since 2001, all patent costs are expensed as incurred. License costs are capitalized and amortized over the estimated life of the related license agreement.

Revenue Recognition

'

Revenue Recognition

We currently recognize revenue resulting from the licensing and use of our technology and intellectual property, from government grants, from services provided to third parties, and from product sales. Licensing agreements may contain multiple elements, such as upfront fees, payments related to the achievement of particular milestones and royalties. Revenue from upfront fees for licensing agreements that contain multiple elements are generally deferred and recognized on a straight-line basis over the term of the agreement. Fees associated with substantive at risk performance-based milestones are recognized as revenue upon completion of the scientific or regulatory event specified in the agreement, and royalties received are recognized as earned. Revenue from licensing agreements is recognized net of a fixed percentage due to licensors as royalties. Grant revenue from government agencies are funds received to cover specific expenses and are recognized as earned upon either the incurring of reimbursable expenses directly related to the particular research plan or the completion of certain development milestones as defined within the terms of the relevant collaborative agreement or grant. Revenue from services to third parties is recognized when we have provided the agreed upon services. Revenue from product sales are recognized when the product is shipped and the order fulfilled.

Stock-Based Compensation

'

Stock-Based Compensation

Compensation expense for stock-based payment awards to employees is based on their grant date fair value as calculated and amortized over their vesting period. See Note 5, “Stock-Based Compensation” for further information.

We use the Black-Scholes model to calculate the fair value of stock-based awards.

Per Share Data

'

Per Share Data

Basic net income or loss per share is computed by dividing net income or loss by the weighted average number of shares of common stock outstanding during the period. Diluted net income or loss per share is computed based on the weighted average number of shares of common stock and other dilutive securities. To the extent these securities are anti-dilutive, they are excluded from the calculation of diluted earnings per share.

The following is a reconciliation of the numerators and denominators of the basic and diluted net loss per share computations:

Three months ended September 30,

Nine months ended September 30,

2013

2012

2013

2012

Net loss

$

(7,191,653

)

$

(16,336,790

)

$

(19,476,782

)

$

(25,732,707

)

Weighted average shares outstanding used to compute basic and diluted net income or loss per share

41,402,717

30,168,475

39,787,527

25,992,764

Basic and diluted net loss per share

$

(0.17

)

$

(0.54

)

$

(0.49

)

$

(0.99

)

The following outstanding potentially dilutive securities were excluded from the computation of diluted net income or loss per share because the effect would have been anti-dilutive as of September 30:

2013

2012

Options

431,558

474,917

Restricted stock units

3,336,282

1,516,199

Warrants

9,894,909

10,689,083

Total

13,662,749

12,680,199

Comprehensive Income (Loss)

'

Comprehensive Income (Loss)

Comprehensive income (loss) is comprised of net income or loss and other comprehensive income or loss (OCL). OCL includes certain changes in stockholders’ equity that are excluded from net income or loss. Specifically, we include in OCL changes in unrealized gains and losses on our marketable securities and unrealized gains and losses on foreign currency translations. Accumulated other comprehensive income was $170,605, as of September 30, 2013, and accumulated other comprehensive income was $193,177, as of December 31, 2012.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Basic and Dilutive Net Loss Per Share Computations	'
	The following is a reconciliation of the numerators and denominators of the basic and diluted net loss per share computations:
		Three months ended September 30,						Nine months ended September 30,
		2013			2012			2013			2012
	Net loss	$	(7,191,653	)	$	(16,336,790	)	$	(19,476,782	)	$	(25,732,707	)
	Weighted average shares outstanding used to compute basic and diluted net income or loss per share		41,402,717			30,168,475			39,787,527			25,992,764
	Basic and diluted net loss per share	$	(0.17	)	$	(0.54	)	$	(0.49	)	$	(0.99	)
Outstanding Options, Warrants and Restricted Stock Units	'
	The following outstanding potentially dilutive securities were excluded from the computation of diluted net income or loss per share because the effect would have been anti-dilutive as of September 30:
		2013			2012
	Options		431,558			474,917
	Restricted stock units		3,336,282			1,516,199
	Warrants		9,894,909			10,689,083
	Total		13,662,749			12,680,199

Financial_Instruments_Tables

Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2013
Investments Debt And Equity Securities [Abstract]	'
Available for Sale Securities Held in Investment Portfolio	'
	The following table summarizes the fair value of our cash, cash equivalents and available-for-sale marketable securities held in our current investment portfolio:
		Amortized		Gross			Fair Value
		Cost		Unrealized
				(Losses)
	September 30, 2013
	Cash	$	377,695	$	—		$	377,695
	Cash equivalents		20,577,598		—			20,577,598
	Total cash, cash equivalents, and marketable securities	$	20,955,293	$	—		$	20,955,293
	December 31, 2012
	Cash	$	254,267	$	—		$	254,267
	Cash equivalents		8,217,259		(252	)		8,217,007
	Marketable debt securities, current		13,901,782		(1,104	)		13,900,678
	Total cash, cash equivalents, and marketable securities	$	22,373,308	$	(1,356	)	$	22,371,952

Fair_Value_Measurement_Tables

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Financial Assets and Liabilities Measured at Fair Value	'
	The following table presents financial assets and liabilities measured at fair value as of September 30, 2013:
		Fair Value Measurement
		at Report Date Using
		Quoted Prices			Significant			Unobservable			As of
		in Active Markets			Other			Inputs			September 30,
		for			Observable			(Level 3)			2013
		Identical Assets			Inputs
		(Level 1)			(Level 2)
	Financial assets:
	Cash equivalents:
	Money market funds	$	377,695		$	—		$	—		$	377,695
	U.S. Treasury debt obligations		20,577,598			—			—			20,577,598
	Total financial assets	$	20,955,293		$	—		$	—		$	20,955,293
	Financial liabilities:
	Bond obligation	$	—		$	178,750		$	—		$	178,750
	Loan payable net of discounts		—			—			13,468,348			13,468,348
	Warrant liabilities		—			15,260			8,405,694			8,420,954
	Total financial liabilities	$	—		$	194,010		$	21,874,042		$	22,068,052
Roll Forward for Financial Assets and Liabilities Measured at Fair Value Using Significant Other Observable Inputs (Level 2)	'
	Level 2 Reconciliation
	The following table presents a roll forward for financial assets and liabilities measured at fair value using significant other observable inputs (Level 2) for 2013:
		Level 2			Net transfers (to)			Change			Settled			Level 2
		Beginning			from			included in			$			Ending
		Balance 12/31/12			Level 1			earnings						Balance 09/30/13
		$			$			$						$
	Marketable securities		13,900,678			(13,900,678	)		—			—			—
	Bond obligation		331,250			—			—			(152,500	)		178,750
	Warrant liabilities		107,968			—			(92,708	)		—			15,260
Roll Forward for Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3)	'
	Level 3 Reconciliation
	The following table presents a roll forward for liabilities measured at fair value using significant unobservable inputs (Level 3) for 2013.
		Warrant
		Liabilities
	Balance at December 31, 2012	$	9,157,397
	Less fair value of warrants exercised		(418,841	)
	Add change in fair value of warrants		(332,862	)
	Balance at September 30, 2013	$	8,405,694
		Loan payable net of discounts
	Loan proceeds	$	13,820,264
	Less discount		(487,576	)
	Add amortization of discount		135,660
	Balance at September 30, 2013	$	13,468,348

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'
Purchase Price Allocated	'
	The purchase price was allocated as follows:
		Allocated purchase			Estimated life of
		Price			intangible assets
					in years
	Net tangible assets	$	36,000
	Intangible assets:
	Customer relationships and developed technology		1,310,000			6 to 9
	In-process research and development		1,340,000			N/A
	Trade name		310,000			15
	Goodwill		2,139,000			N/A
	Total	$	5,135,000
Changes in Goodwill	'
	The following table presents changes in goodwill:
	Balance as of December 31, 2012	$	1,983,426
	Foreign currency translation		(10,124	)
	Balance as of September 30, 2013	$	1,973,302
Components of Other Intangible Assets	'
	The components of our other intangible assets at September 30, 2013 are summarized below:
	Other Intangible Asset Class	Cost			Additions		Impairment			Accumulated			Foreign Currency		Net Carrying		Weighted-
										Amortization			Translation		Amount		Average
																	Amortization
																	Period
	Customer relationships and developed technology	$	1,310,000		$	—	$	—		$	(829,204	)	$	142,683	$	623,479		8.0 years
	In-process research and development		1,340,000			—		(654,961	)		(270,687	)		133,300		547,652		Indefinite
	Trade name		310,000			—		—			(102,118	)		35,913		243,795		15.0 years
	Patents		979,612			64,000		—			(785,487	)		—		258,125		16.0 years
	Total other intangible assets	$	3,939,612		$	64,000	$	(654,961	)	$	(1,987,496	)	$	311,896	$	1,673,051		12.2 years
Expected Future Annual Amortization Expense	'
	The expected future annual amortization expense for each of the next five years based on current balances of our intangible assets is approximately as follows:
	For the year ending December 31:
	2013	$	289,000
	2014	$	275,000
	2015	$	275,000
	2016	$	267,000
	2017	$	247,000

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock-Based Compensation Expense	'
	Our stock-based compensation expense for the three and nine months ended September 30 was as follows:
			Three months ended						Nine months ended
			September 30,						September 30,
			2013			2012			2013			2012
	Research and development expense		$	346,938		$	314,393		$	1,064,301		$	966,570
	Selling, general and administrative expense			250,067			452,760			968,927			1,260,575
	Total stock-based compensation		$	597,005		$	767,153		$	2,033,228		$	2,227,145
	Effect on basic and diluted net loss per share		$	(0.01	)	$	(0.03	)	$	(0.05	)	$	(0.09	)
Stock Option Activity	'
	A summary of our stock option activity for the three months ended September 30, 2013 is as follows:
			Number of options			Weighted-average
						exercise price ($) per share
	Balance at June 30, 2013			440,126			19.85
	Granted			—			—
	Exercised			(723	)		1
	Cancelled			(7,845	)		18.87
	Outstanding options at September 30, 2013			431,558			19.9
Summary of Changes in Unvested Options	'
	A summary of changes in unvested options for the three months ended September 30, 2013 is as follows:
			Number of options			Weighted-average			Weighted-average
						exercise price ($) per share			grant
									date fair value ($) per option
	Unvested options at June 30, 2013			39,097			10.37			8.25
	Granted			—			—			—
	Vested			(10,374	)		10.55			8.38
	Cancelled			—			—			—
	Unvested options at September 30, 2013			28,723			10.31			8.2
Summary of Changes in Unvested Restricted Stock Units	'
	A summary of changes in our restricted stock units for the three months ended September 30, 2013 is as follows:
			Number of RSUs			Weighted-average
						grant
						date fair value ($) per RSU
	Outstanding restricted stock units at June 30, 2013			3,350,616			1.7
	Granted(1)			60,000			1.73
	Vested and exercised			(30,334	)		3.26
	Cancelled			(44,000	)		2.01
	Outstanding restricted stock units at September 30, 2013			3,336,282			1.68
	-1	10,000 of these restricted stock units vest and convert into shares of our common stock after one year from the date of grant. 50,000 of these restricted stock units will vest and convert into shares of our common stock over a four year period from the date of grant; one-fourth of the award will vest on each grant date anniversary following the grant.
Summary of Changes in SARs	'
	A summary of the changes in SARs for the three months ended September 30, 2013 is as follows:
			Number of SARs
	Outstanding at June 30, 2013			110,593
	Granted			—
	Exercised			—
	Forfeited and expired			—
	Outstanding SARs at September 30, 2013			110,593
	SARs exercisable at September 30, 2013			110,593

WindDown_Expenses_Tables

Wind-Down Expenses (Tables)	9 Months Ended
	Sep. 30, 2013
Restructuring And Related Activities [Abstract]	'
Summary of Changes to Wind-Down Reserve	'
	The summary of the changes to our wind-down reserve related to this facility for 2013 and 2012 were as follows:
		January 1 to			April 1 to			January 1 to			January 1 to
		March 31,			June 30,			June 30,			December 31,
		2013			2013			2013			2012
	Accrued wind-down reserve at beginning of period	$	854,000		$	505,000		$	854,000		$	1,683,000
	Less actual expenses recorded against estimated reserve during the period		(372,000	)		(505,000	)		(877,000	)		(1,185,000	)
	Additional expense recorded to revise estimated reserve at period-end		23,000			—			23,000			356,000
	Revised reserve at period-end		505,000			—			—			854,000
	Add deferred rent at period-end		124,000			—			—			249,000
	Total accrued wind-down expenses at period-end, current	$	629,000		$	—		$	—		$	1,103,000

Loan_Payable_Tables

Loan Payable (Tables)	9 Months Ended
	Sep. 30, 2013
Warrant Agreement 2008 [Member]	'
Assumptions Used for Black-Scholes Option Pricing Model	'
	The assumptions used for the Black-Scholes option pricing model are as follows:
		To Calculate
		Fair Value of Warrant
		Liability at
		September 30, 2013			December 31, 2012
	Expected life (years)		0.6			1.4
	Risk-free interest rate		0.1	%		0.2	%
	Expected volatility		40.2	%		108.2	%
	Expected dividend yield		0	%		0	%
		At September 30,			At December 31,			Change in Fair Value
		2013			2012			of Warrant Liability
	Fair value of liability for warrants issued in 2008	$	0		$	44,628		$	(44,628	)
Warrant Agreement 2009 [Member]	'
Assumptions Used for Black-Scholes Option Pricing Model	'
	The assumptions used for the Black-Scholes option pricing model are as follows:
		To Calculate
		Fair Value of Warrant Liability at
		September 30,			December 31,
		2013			2012
	Expected life (years)		1.6			2.3
	Risk-free interest rate		0.3	%		0.3	%
	Expected volatility		86.1	%		94.5	%
	Expected dividend yield		0	%		0	%
		At September 30,			At December 31,			Change in Fair Value
		2013			2012			of Warrant Liability
	Fair value of liability for warrants issued in 2009	$	15,260		$	63,340		$	(48,080	)
Silicon Valley Bank Loan Agreement Warrant [Member]	'
Assumptions Used for Black-Scholes Option Pricing Model	'
	We estimated the fair value of the warrant to be approximately $388,000 using the Black-Scholes option pricing model with the following assumptions:
	Expected life (years)		10
	Risk-free interest rate		1.9	%
	Expected volatility		88.1	%
	Expected dividend yield		0	%

Warrant_Liability_Tables

Warrant Liability (Tables)	9 Months Ended
	Sep. 30, 2013
Text Block [Abstract]	'
Assumptions Used for Simulation Model	'
	The assumptions used for the Monte Carlo simulation model to value the Series A Warrants at September 30, 2013 are as follows:
	Risk-free interest rate per year		0.7	%
	Expected volatility per year		83.6	%
	Expected dividend yield		0	%
	Expected life in years		3.2
Summary of Changes in Fair Value of Warrant Liability	'
	The following table is a summary of the changes in fair value of warrant liability for the Series A Warrants for the nine-month period ended September 30, 2013:
		Series A
		Number of			Fair value $
		Warrants
	Balance at December 31, 2012		8,501,429		$	9,157,397
	Less exercised		(334,534	)		(418,841	)
	Changes in fair value		—			(332,862	)
	Balance at September 30, 2013		8,166,895		$	8,405,694
Summary of Outstanding Warrants and Fair Value of Warrant Liability	'
	The following table is a summary of our warrant liability as of September 30, 2013:
	Warrants	Number Outstanding			Exercise Price ($)			Fair value
					per share
	Warrants issued in 2008		1,034,483			23		$	—
	Warrants issued in 2009		400,000			15			15,260
	Series A Warrants		8,166,895			1.4			8,405,694
	Total		9,601,378					$	8,420,954

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2013
Text Block [Abstract]	'
Summary of Changes in Accumulated Other Comprehensive Loss by Component	'
	The following table sets forth the changes in accumulated other comprehensive loss by component for the three months ended September 30, 2013:
		Unrealized Gain			Foreign Currency			Total
		on Other			Translation
		Available-for-Sale
		Securities
	Beginning balance	$	425		$	(35,515	)	$	(35,090	)
	Other comprehensive income before reclassifications		(425	)		206,121			205,696
	Amounts reclassified from accumulated other comprehensive loss		—			—			—
	Net current-period other comprehensive income (loss)		(425	)		206,121			205,696
	Ending balance	$	—		$	170,606		$	170,606

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)

9 Months Ended

3 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

1 Months Ended

Sep. 30, 2013

Jun. 30, 2013

Dec. 31, 2012

Sep. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2011

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2011

Dec. 31, 2011

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Nov. 30, 2008

Nov. 30, 2008

Sep. 30, 2013

Sep. 30, 2013

Nov. 30, 2009

Nov. 30, 2009

Segment

Warrant liabilities [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

November 2008 Financing [Member]

November 2008 Financing [Member]

November 2008 Financing [Member]

November 2008 Financing [Member]

November 2009 Financing [Member]

November 2009 Financing [Member]

November 2009 Financing [Member]

November 2009 Financing [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series B Warrants [Member]

Series B Warrants [Member]

Warrant liabilities [Member]

Common Stock [Member]

Warrant liabilities [Member]

Warrant liabilities [Member]

Common Stock [Member]

Warrant liabilities [Member]

Common Stock [Member]

Class of Warrant or Right [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of segments

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maturity period for market accounts, money market funds and investments

'90 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrant component

'

'

'

'

'

'

1

'

'

1

'

'

'

'

'

0.75

'

'

'

0.4

'

Number of securities callable by warrants

'

'

'

'

'

'

'

8,000,000

'

'

'

8,000,000

'

'

'

1,034,483

'

'

'

400,000

'

Exercise price of warrants

'

'

'

'

'

'

'

'

'

'

1.4

1.25

'

23

'

23

'

15

'

15

'

Term of warrant

'

'

'

'

'

'

'

'5 years

'

'

'

'90 days

'

'

'

'

'5 years

'

'

'

'5 years

Number of warrants exercised

'

'

'

'

'

'

'

'

'

'

'

'

2,700,000

'

'

'

'

'

'

'

'

Number of shares issued upon Series B warrants exercise

'

'

'

'

334,534

2,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of warrants issued upon Series B warrants exercise

'

'

'

'

'

'

'

'

2,700,000

'

'

'

'

'

'

'

'

'

'

'

'

Number of warrants expired

'

'

'

'

'

'

'

'

'

'

'

'

5,300,000

'

'

'

'

'

'

'

'

Fair value of derivative liability

'

'

'

$8,420,954

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$15,260

'

'

Impairment of goodwill

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Value of patent

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Accumulated other comprehensive income

$170,605

($35,090)

$193,177

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Basic and Dilutive Net loss Per Share Computations (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accounting Policies [Abstract]	'	'	'	'
Net loss	($7,191,653)	($16,336,790)	($19,476,782)	($25,732,707)
Weighted average shares outstanding used to compute basic and diluted net income or loss per share	41,402,717	30,168,475	39,787,527	25,992,764
Basic and diluted net loss per share	($0.17)	($0.54)	($0.49)	($0.99)

Summary_of_Significant_Account5

Summary of Significant Accounting Policies - Outstanding Options, Warrants and Restricted Stock Units (Detail)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Class of Stock [Line Items]	'	'
Outstanding options, warrants and restricted stock units	13,662,749	12,680,199
Options [Member]	'	'
Class of Stock [Line Items]	'	'
Outstanding options, warrants and restricted stock units	431,558	474,917
Restricted stock units [Member]	'	'
Class of Stock [Line Items]	'	'
Outstanding options, warrants and restricted stock units	3,336,282	1,516,199
Warrant liabilities [Member]	'	'
Class of Stock [Line Items]	'	'
Outstanding options, warrants and restricted stock units	9,894,909	10,689,083

Financial_Instruments_Availabl

Financial Instruments - Available for Sale Securities Held in Investment Portfolio (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	$20,955,293	$22,373,308
Gross Unrealized (Losses)	'	-1,356
Fair Value	20,955,293	22,371,952
Cash [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	377,695	254,267
Gross Unrealized (Losses)	'	'
Fair Value	377,695	254,267
Cash equivalents [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	20,577,598	8,217,259
Gross Unrealized (Losses)	'	-252
Fair Value	20,577,598	8,217,007
Marketable debt securities, current [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	'	13,901,782
Gross Unrealized (Losses)	'	-1,104
Fair Value	'	$13,900,678

Financial_Instruments_Addition

Financial Instruments - Additional Information (Detail) (Subsidiaries [Member], USD $)	Sep. 30, 2013
Subsidiaries [Member]	'
Cash and Cash Equivalents [Line Items]	'
Cash	$114,000

Fair_Value_Measurement_Financi

Fair Value Measurement - Financial Assets and Liabilities Measured at Fair Value (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Warrant liabilities [Member]	'	'
Financial liabilities:	'	'
Total financial liabilities	$8,420,954	'
Fair Value, Measurements [Member]	'	'
Financial assets:	'	'
Total financial assets	20,955,293	'
Financial liabilities:	'	'
Total financial liabilities	22,068,052	'
Fair Value, Measurements [Member] | Money market funds [Member] | Cash equivalents [Member]	'	'
Financial assets:	'	'
Total financial assets	377,695	'
Fair Value, Measurements [Member] | U.S. Treasury debt obligations [Member] | Cash equivalents [Member]	'	'
Financial assets:	'	'
Total financial assets	20,577,598	'
Fair Value, Measurements [Member] | Bond obligation [Member]	'	'
Financial liabilities:	'	'
Total financial liabilities	178,750	'
Fair Value, Measurements [Member] | Loan payable net of discounts [Member]	'	'
Financial liabilities:	'	'
Total financial liabilities	13,468,348	'
Fair Value, Measurements [Member] | Warrant liabilities [Member]	'	'
Financial liabilities:	'	'
Total financial liabilities	8,420,954	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements [Member]	'	'
Financial assets:	'	'
Total financial assets	20,955,293	'
Financial liabilities:	'	'
Total financial liabilities	'	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements [Member] | Money market funds [Member] | Cash equivalents [Member]	'	'
Financial assets:	'	'
Total financial assets	377,695	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements [Member] | U.S. Treasury debt obligations [Member] | Cash equivalents [Member]	'	'
Financial assets:	'	'
Total financial assets	20,577,598	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements [Member] | Bond obligation [Member]	'	'
Financial liabilities:	'	'
Total financial liabilities	'	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements [Member] | Loan payable net of discounts [Member]	'	'
Financial liabilities:	'	'
Total financial liabilities	'	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements [Member] | Warrant liabilities [Member]	'	'
Financial liabilities:	'	'
Total financial liabilities	'	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements [Member]	'	'
Financial assets:	'	'
Total financial assets	'	'
Financial liabilities:	'	'
Total financial liabilities	194,010	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements [Member] | Money market funds [Member] | Cash equivalents [Member]	'	'
Financial assets:	'	'
Total financial assets	'	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements [Member] | U.S. Treasury debt obligations [Member] | Cash equivalents [Member]	'	'
Financial assets:	'	'
Total financial assets	'	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements [Member] | Bond obligation [Member]	'	'
Financial assets:	'	'
Total financial assets	178,750	331,250
Financial liabilities:	'	'
Total financial liabilities	178,750	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements [Member] | Loan payable net of discounts [Member]	'	'
Financial liabilities:	'	'
Total financial liabilities	'	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements [Member] | Warrant liabilities [Member]	'	'
Financial assets:	'	'
Total financial assets	15,260	107,968
Financial liabilities:	'	'
Total financial liabilities	15,260	'
UNobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member]	'	'
Financial assets:	'	'
Total financial assets	'	'
Financial liabilities:	'	'
Total financial liabilities	21,874,042	'
UNobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member] | Money market funds [Member] | Cash equivalents [Member]	'	'
Financial assets:	'	'
Total financial assets	'	'
UNobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member] | U.S. Treasury debt obligations [Member] | Cash equivalents [Member]	'	'
Financial assets:	'	'
Total financial assets	'	'
UNobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member] | Bond obligation [Member]	'	'
Financial liabilities:	'	'
Total financial liabilities	'	'
UNobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member] | Loan payable net of discounts [Member]	'	'
Financial liabilities:	'	'
Total financial liabilities	13,468,348	'
UNobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member] | Warrant liabilities [Member]	'	'
Financial liabilities:	'	'
Total financial liabilities	$8,405,694	'

Fair_Value_Measurement_Roll_Fo

Fair Value Measurement - Roll Forward for Financial Assets and Liabilities Measured at Fair Value Using Significant Other Observable Inputs (Level 2) (Detail) (Fair Value, Measurements [Member], USD $)	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012
		Significant Other Observable Inputs Level 2 [Member]	Significant Other Observable Inputs Level 2 [Member]	Significant Other Observable Inputs Level 2 [Member]	Significant Other Observable Inputs Level 2 [Member]	Significant Other Observable Inputs Level 2 [Member]
			Bond obligation [Member]	Warrant liabilities [Member]	Marketable securities [Member]	Marketable securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Marketable debt securities, Beginning Balance	$20,955,293	'	$331,250	$107,968	'	$13,900,678
Fair Value Measurement With Unobservable inputs reconciliation recurring basis asset transfers into level 1	'	'	'	'	-13,900,678	'
Financial liabilities change included in earning fair value disclosure	'	'	'	-92,708	'	'
Financial liabilities change settled in earning fair value disclosure	'	'	-152,500	'	'	'
Marketable debt securities, ending Balance	$20,955,293	'	$178,750	$15,260	'	$13,900,678

Fair_Value_Measurement_Roll_Fo1

Fair Value Measurement - Roll Forward for Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3) (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Warrant liabilities [Member]	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'
Balance at December 31, 2012	$9,157,397
Less fair value of warrants exercised	-418,841
Add change in fair value of warrants	-332,862
Balance at September 30, 2013	8,405,694
Loan payable net of discounts [Member]	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'
Loan proceeds	13,820,264
Less discount	-487,576
Add amortization of discount	135,660
Balance at September 30, 2013	$13,468,348

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended			1 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2011	Mar. 31, 2009	Apr. 01, 2009	Sep. 30, 2013	Sep. 30, 2013
					Trade name [Member]	Trade name [Member]	In-process research and development [Member]
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'	'	'	'	'
Aggregate purchase price	'	'	'	$5,135,000	'	'	'
Minimum expiration year of intangible assets	'	'	'	'	'	'	'2027
Impairment amount of intangible asset	'	'	655,000	'	'	'	'
Useful life	'	'12 years 2 months 12 days	'	'	'15 years	'15 years	'
Amortization expense	$66,000	'	'	'	'	'	'

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets - Purchase Price Allocated (Detail) (USD $)	1 Months Ended	9 Months Ended
	Apr. 01, 2009	Sep. 30, 2013	Mar. 31, 2009
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'
Weighted Average Amortization Period	'	'12 years 2 months 12 days	'
Net tangible assets	'	'	$36,000
Total	'	'	5,135,000
Customer relationships and developed technology [Member]	'	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'
Weighted Average Amortization Period	'	'8 years	'
Allocated Purchase Price	'	'	1,310,000
Customer relationships and developed technology [Member] | Minimum [Member]	'	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'
Weighted Average Amortization Period	'6 years	'	'
Customer relationships and developed technology [Member] | Maximum [Member]	'	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'
Weighted Average Amortization Period	'9 years	'	'
In-process research and development [Member]	'	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'
Allocated Purchase Price	'	'	1,340,000
Trade name [Member]	'	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'
Weighted Average Amortization Period	'15 years	'15 years	'
Allocated Purchase Price	'	'	310,000
Goodwill [Member]	'	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'
Weighted Average Amortization Period	'	'	'
Goodwill	'	'	$2,139,000

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets - Changes in Goodwill (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'
Balance as of December 31, 2012	$1,983,426
Foreign currency translation	-10,124
Balance as of September 30, 2013	$1,973,302

Goodwill_and_Other_Intangible_5

Goodwill and Other Intangible Assets - Components of Other Intangible Assets (Detail) (USD $)	9 Months Ended		9 Months Ended		1 Months Ended	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2013	Apr. 01, 2009	Sep. 30, 2013	Sep. 30, 2013
			Customer relationships and developed technology [Member]	In-process research and development [Member]	Trade name [Member]	Trade name [Member]	Patents [Member]
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'	'	'	'	'
Cost	$3,939,612	'	$1,310,000	$1,340,000	'	$310,000	$979,612
Additions	64,000	'	'	'	'	'	64,000
Impairment	-654,961	'	'	-654,961	'	'	'
Accumulated Amortization	-1,987,496	'	-829,204	-270,687	'	-102,118	-785,487
Foreign Currency Translation	311,896	'	142,683	133,300	'	35,913	'
Net Carrying Amount	$1,673,051	$1,822,904	$623,479	$547,652	'	$243,795	$258,125
Weighted Average Amortization Period	'12 years 2 months 12 days	'	'8 years	'	'15 years	'15 years	'16 years

Goodwill_and_Other_Intangible_6

Goodwill and Other Intangible Assets - Expected Future Annual Amortization Expense (Detail) (USD $)	Sep. 30, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'
2013	$289,000
2014	275,000
2015	275,000
2016	267,000
2017	$247,000

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012
		Incentive_Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Shares authorized	75,000,000	75,000,000	75,000,000
Equity Incentive Plans	'	2	'
Total unrecognized compensation expense	$4,767,000	$4,767,000	'
Vesting period	'	'3 years 2 months 12 days	'
Vesting period of grant date	'1 year	'	'
Exercise price	$20	$20	'
Equity Incentive Plan [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Shares authorized	2,601,389	2,601,389	'
Annual increase in number of shares of common stock	4.00%	4.00%	'
Aggregate limit of shares issuable to incentive stock option awards	3,000,000	3,000,000	'
Stock Appreciation Rights (SARs) [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Vesting period of grant date	'	'3 years	'
Percentage of vested grant yearly	'	25.00%	'
Percentage of vested grant monthly	'	75.00%	'
Stock Appreciation Rights (SARs) [Member] | Maximum [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Term of years	'	'10 years	'
Restricted Stock Three [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Restricted stock units vest and convert into shares of our common stock	'	'4 years	'
Options [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Term of years	'	'4 years	'
Percentage of vested grant yearly	'	25.00%	'
Percentage of vested grant monthly	'	75.00%	'
Unexercised vested option forfeiture	'	'3 months	'
Estimated fair value	$87,000	'	'
Options [Member] | Maximum [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Term of years	'	'10 years	'
Vesting period of grant date	'	'3 years	'

StockBased_Compensation_StockB

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Total stock-based compensation	$597,005	$767,153	$2,033,228	$2,227,145
Effect on basic and diluted net loss per share	($0.01)	($0.03)	($0.05)	($0.09)
Research and development expense [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Total stock-based compensation	346,938	314,393	1,064,301	966,570
Selling, general and administrative expense [Member]	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Total stock-based compensation	$250,067	$452,760	$968,927	$1,260,575

StockBased_Compensation_Stock_

Stock-Based Compensation - Stock Option Activity (Detail) (USD $)	3 Months Ended
	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Number of options, Beginning balance	440,126
Number of options, Granted	'
Number of options, Exercised	-723
Number of options, Cancelled	-7,845
Number of options, Ending balance	431,558
Weighted-average exercise price per share, Beginning balance	$19.85
Weighted-average exercise price per share, Granted	'
Weighted-average exercise price, Exercised	$1
Weighted-average exercise price, Cancelled	$18.87
Weighted-average exercise price per share, Ending balance	$19.90

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Changes in Unvested Options (Detail) (USD $)	3 Months Ended
	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Weighted-average exercise price per share, Beginning balance	$19.85
Weighted-average exercise price per share, Granted	'
Weighted-average exercise price per share, Ending balance	$19.90
Unvested stock options [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of options, Beginning balance	39,097
Number of options, Granted	'
Number of options, Vested	-10,374
Number of options, Cancelled	'
Number of options, Ending balance	28,723
Weighted-average exercise price per share, Beginning balance	$10.37
Weighted-average exercise price per share, Granted	'
Weighted-average exercise price per share, Vested	$10.55
Weighted-average exercise price per share, Cancelled	'
Weighted-average exercise price per share, Ending balance	$10.31
Weighted-average grant date fair value per option, Beginning balance	$8.25
Weighted-average grant date fair value per option, Granted	'
Weighted-average grant date fair value per option, Vested	$8.38
Weighted-average grant date fair value per option, Cancelled	'
Weighted-average grant date fair value per option, Ending balance	$8.20

StockBased_Compensation_Summar1

Stock-Based Compensation - Summary of Changes in Unvested Restricted Stock Units (Detail) (Restricted stock units [Member], USD $)	3 Months Ended
	Sep. 30, 2013
Restricted stock units [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of RSUs, Beginning balance	3,350,616
Number of RSUs, Granted	60,000
Number of RSUs, Vested	-30,334
Number of RSUs, Cancelled	-44,000
Number of RSUs, Ending balance	3,336,282
Weighted-average grant date fair value per RSU, Beginning balance	$1.70
Weighted-average grant date fair value per RSU, Granted	$1.73
Weighted-average grant date fair value per RSU, Vested	$3.26
Weighted-average grant date fair value per RSU, Cancelled	$2.01
Weighted-average grant date fair value per RSU, Ending balance	$1.68

StockBased_Compensation_Summar2

Stock-Based Compensation - Summary of Changes in Unvested Restricted Stock Units (Parenthetical) (Detail)	3 Months Ended
	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of restricted unit vest and convert into common stock over next fiscal year	10,000
Number of restricted unit would vest over vesting period	50,000
Vesting period of grant date	'1 year
Restricted stock units vested description after specified period	25
Restricted stock unit vest description	'50,000 of these restricted stock units will vest and convert into shares of our common stock over a four year period
Restricted Stock One [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Restricted stock units vest and convert into shares of our common stock	'4 years

StockBased_Compensation_Summar3

Stock-Based Compensation - Summary of Changes in SARs (Detail) (Stock Appreciation Rights (SARs) [Member])	3 Months Ended
	Sep. 30, 2013
Stock Appreciation Rights (SARs) [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of SARs, Beginning balance	110,593
Number of SARs, Granted	'
Number of SARs, Exercised	'
Number of SARs, Forfeited and expired	'
Number of SARs, Ending balance	110,593
SARs Exercisable, Ending balance	110,593

WindDown_Expenses_Additional_I

Wind-Down Expenses - Additional Information (Detail) (USD $)	3 Months Ended
	Jun. 30, 2013	Mar. 31, 2013
Wind Down Expenses [Abstract]	'	'
Amount of wind-down reserve	'	$505,000
Payments net of subtenant income recorded against reserve	505,000	'
Additional expense recorded to revise estimated reserve at period-end	$39,000	'

WindDown_Expenses_Summary_of_C

Wind-Down Expenses - Summary of Changes to Wind-Down Reserve (Detail) (USD $)	3 Months Ended	9 Months Ended		3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2013	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
				Facility Closing In Rhode Island [Member]	Facility Closing In Rhode Island [Member]	Facility Closing In Rhode Island [Member]	Facility Closing In Rhode Island [Member]
Restructuring Cost and Reserve [Line Items]	'	'	'	'	'	'	'
Accrued wind-down reserve at beginning of period	$505,000	'	'	$505,000	$854,000	$854,000	$1,683,000
Less actual expenses recorded against estimated reserve during the period	505,000	'	'	-505,000	-372,000	-877,000	-1,185,000
Additional expense recorded to revise estimated reserve at period-end	'	'	'	'	23,000	23,000	356,000
Revised reserve at period-end	'	'	'	'	505,000	'	854,000
Add deferred rent at period-end	'	-431,390	-69,997	'	124,000	'	249,000
Total accrued wind-down expenses at period-end, current	'	'	'	'	$629,000	'	$1,103,000

Loan_Payable_Additional_Inform

Loan Payable - Additional Information (Detail) (USD $)	9 Months Ended	1 Months Ended			9 Months Ended			1 Months Ended
	Sep. 30, 2013	Jul. 31, 2013	Apr. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2013	Apr. 30, 2013
		CIRM Loan Agreement [Member]	CIRM Loan Agreement [Member]	CIRM Loan Agreement [Member]	CIRM Loan Agreement [Member]	Silicon Valley Bank Loan Agreement Warrant [Member]	Silicon Valley Bank Loan Agreement Warrant [Member]	Silicon Valley Bank [Member]
							Common Stock [Member]
Debt Instrument [Line Items]	'	'	'	'	'	'	'	'
Proceeds from loan	'	'	'	'	'	'	'	$9,900,000
Loan term	'3 years	'	'	'10 years	'	'	'	'
Annual interest rate on loan	6.00%	'	'	'	'	'	'	'
Period of loan subject to interest payments only	'6 months	'	'	'	'	'	'	'
Period of loan subject to principal and interest payments	'30 months	'	'	'	'	'	'	'
Final fee payment at the end of loan term	1,000,000	'	'	'	'	'	'	'
Term of warrants expiration	'	'	'	'	'	'10 years	'	'
Number of shares of common stock acquired using warrants	'	'	'	'	'	'	293,531	'
Exercise price of warrants	'	'	'	'	'	1.7034	'	'
Warrants expiration period	'	'	'	'	'	'April 2023	'	'
Proceeds received under loan agreement	9,900,000	'	'	'	'	'	'	'
Initial carrying amount assigned to loan, net of discount	9,512,000	'	'	'	'	'	'	'
Fair value allocated to warrant	388,000	'	'	'	'	'	'	'
Cash discount	100,000	'	'	'	'	'	'	'
Note issuance costs	117,000	'	'	'	'	'	'	'
Deferred financing costs, discount and accretion percentage	9.00%	'	'	'	'	'	'	'
Approval of fund by California Institute for Regenerative Medicine (CIRM)	'	'	19,300,000	'	'	'	'	'
Approval of fund by California Institute for Regenerative Medicine (CIRM) maximum period	'	'	'	'4 years	'	'	'	'
Loan interest rate description	'	'	'	'	'one year LIBOR rate plus two percent	'	'	'
LIBOR rate plus percentage	'	'	'	'	2.00%	'	'	'
LIBOR rate plus percentage increase	'	'	'	'	1.00%	'	'	'
Proceeds from initial disbursement of the loan	'	$3,800,000	'	'	'	'	'	'

Loan_Payable_Assumptions_Used_

Loan Payable - Assumptions Used for Black-Scholes Option Pricing Model (Detail) (Silicon Valley Bank Loan Agreement Warrant [Member])	9 Months Ended
	Sep. 30, 2013
Silicon Valley Bank Loan Agreement Warrant [Member]	'
Class of Warrant or Right [Line Items]	'
Expected life (years)	'10 years
Risk-free interest rate	1.90%
Expected volatility	88.10%
Expected dividend yield	0.00%

Commitments_and_Contingencies_

Commitments and Contingencies - Additional Information (Detail)

1 Months Ended

9 Months Ended

1 Months Ended

1 Months Ended

9 Months Ended

1 Months Ended

0 Months Ended

1 Months Ended

Jul. 31, 2006

Sep. 30, 2013

Dec. 31, 2012

Mar. 31, 2013

Sep. 30, 2013

Sep. 30, 2010

Sep. 30, 2013

Dec. 31, 2010

Sep. 30, 2013

Dec. 31, 2012

Oct. 31, 2013

Oct. 31, 2013

Claim

USD ($)

USD ($)

Prologis, L.P [Member]

Prologis, L.P [Member]

Caliper Life Sciences, Inc [Member]

Caliper Life Sciences, Inc [Member]

BMR-Gateway Boulevard LLC [Member]

BMR-Gateway Boulevard LLC [Member]

BMR-Gateway Boulevard LLC [Member]

Stem Cell Sciences (U.K.) Ltd [Member]

Stem Cell Sciences (U.K.) Ltd [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Subsequent Events [Member]

Subsequent Events [Member]

Patents

GBP (£)

Commitment And Contingencies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from the issuance of industrial revenue bonds

'

$5,000,000

'

'

'

'

'

'

'

'

'

'

Interest rate for remaining bond series

'

9.50%

'

'

'

'

'

'

'

'

'

'

Outstanding principal

'

179,000

331,000

'

'

'

'

'

'

'

'

'

Period of maturity

'

'2014-08

'

'

'

'

'

'

'

'

'

'

Term of lease

'

'15 years

'

'10 years

'

'2 years

'

'11 years 6 months

'

'

'

'3 years

Rent over term of lease

'

1,165,000

'

3,497,000

'

1,081,000

'

17,869,000

'

'

'

'

Lease term expires

'

30-Jun-13

'

'

'

'

30-Sep-13

'

'

'

'

'

Deferred rent under sublease agreement

'

28,050

'

'

389,000

'

'

'

1,432,000

1,389,000

'

'

Rental payments under the existing lease

'

'

'

'

'

'

'

'

'

'

'

£ 53,000

Number of patients violate claims of Neuralstem's activities

4

'

'

'

'

'

'

'

'

'

'

'

Number of patents acquired

'

'

'

'

'

'

'

'

'

'

6

'

Shares issued

'

329,131

'

'

'

'

'

'

'

'

139,548

139,548

Warrant_Liability_Additional_I

Warrant Liability - Additional Information (Detail) (USD $)

1 Months Ended

3 Months Ended

1 Months Ended

1 Months Ended

1 Months Ended

12 Months Ended

3 Months Ended

9 Months Ended

12 Months Ended

3 Months Ended

9 Months Ended

12 Months Ended

Nov. 30, 2008

Mar. 31, 2013

Sep. 30, 2013

Nov. 30, 2008

Sep. 30, 2013

Nov. 30, 2008

Nov. 30, 2009

Sep. 30, 2013

Nov. 30, 2009

Dec. 31, 2011

Mar. 31, 2013

Sep. 30, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2012

Dec. 31, 2011

Mar. 31, 2013

Sep. 30, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2011

Dec. 31, 2011

Warrant liabilities [Member]

Series A Warrants [Member]

Series A Warrants [Member]

November 2008 Financing [Member]

November 2008 Financing [Member]

November 2008 Financing [Member]

November 2009 Financing [Member]

November 2009 Financing [Member]

November 2009 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

Common Stock [Member]

Common Stock [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series B Warrant [Member]

Series B Warrant [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Capital Units [Member]

Capital Units [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series B Warrant [Member]

Class of Warrant or Right [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of units sold to investors

'

'

'

1,379,310

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Price per unit

'

'

'

$14.50

'

'

$12.50

'

'

$1.25

'

'

'

'

'

'

'

'

'

'

'

'

Gross proceeds from units sold to investors

'

'

'

$20,000,000

'

'

$12,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of securities callable by each warrant or right warrants

'

'

'

'

'

0.75

'

'

0.4

'

'

'

'

'

'

'

'

1

'

'

1

1

Exercise price of warrants

'

'

1.4

'

23

23

'

15

15

'

'

'

'

'

'

'

'

'

'

1.4

'

'

Proceeds from sale of stock

'

$468,000

'

$18,637,000

'

'

$11,985,000

'

'

'

$468,000

'

'

$468,000

'

'

'

'

'

'

'

'

Number of shares of common stock in each unit sold to institutional investors

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of securities callable by warrants

'

'

'

'

'

1,034,483

'

'

400,000

'

'

'

'

8,000,000

'

8,000,000

'

'

'

'

'

'

Number of units sold to investors

'

'

'

'

'

'

1,000,000

'

'

10,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Number of warrants in each unit sold to institutional investors

'

'

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

Term of warrant

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'90 days

'

'

'

'

'

'

Warrant expiration

'

'

'

'

'

'

'

'

'

'

'

'December 2016

'

'2012-May-02

'

'

'

'

'

'

'

'

Number of warrants exercised

'

'

'

'

'

'

'

'

'

'

334,534

2,198,571

'

'

2,700,000

'

'

'

'

'

'

'

Number of shares issued upon warrants exercise

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

334,534

2,198,571

2,700,000

'

'

'

Number of warrants issued

'

'

'

'

'

'

'

'

'

'

'

'

2,700,000

'

'

'

'

'

'

'

'

'

Number of warrants expired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,300,000

'

'

'

'

'

'

'

Number of Series A warrants in each unit issued in public offering

'

'

'

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

Warrant_Liability_Assumptions_

Warrant Liability - Assumptions Used for Black-Scholes Option Pricing Model (Detail) (USD $)	3 Months Ended		9 Months Ended			9 Months Ended	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013	Dec. 31, 2012
						Warrant Agreement 2008 [Member]	Warrant Agreement 2008 [Member]
Class of Warrant or Right [Line Items]	'	'	'	'	'	'	'
Expected life (years)	'	'	'	'	'	'7 months 6 days	'1 year 4 months 24 days
Risk-free interest rate	'	'	'	'	'	0.10%	0.20%
Expected volatility	'	'	'	'	'	40.20%	108.20%
Expected dividend yield	'	'	'	'	'	0.00%	0.00%
Fair value of warrant liability	$8,420,954	'	$8,420,954	'	$9,265,365	$0	$44,628
Change in fair value of warrant liability	$143,511	$11,239,465	($425,570)	$9,974,685	'	($44,628)	'

Warrant_Liability_Assumptions_1

Warrant Liability - Assumptions Used for Black-Scholes Option Pricing Model1 (Detail) (USD $)	3 Months Ended		9 Months Ended			9 Months Ended	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013	Dec. 31, 2012
						Warrant Agreement 2009 [Member]	Warrant Agreement 2009 [Member]
Class of Warrant or Right [Line Items]	'	'	'	'	'	'	'
Expected life (years)	'	'	'	'	'	'1 year 7 months 6 days	'2 years 3 months 18 days
Risk-free interest rate	'	'	'	'	'	0.30%	0.30%
Expected volatility	'	'	'	'	'	86.10%	94.50%
Expected dividend yield	'	'	'	'	'	0.00%	0.00%
Fair value of warrant liability	$8,420,954	'	$8,420,954	'	$9,265,365	$15,260	$63,340
Change in fair value of warrant liability	$143,511	$11,239,465	($425,570)	$9,974,685	'	($48,080)	'

Warrant_Liability_Assumptions_2

Warrant Liability - Assumptions Used for Monte Carlo Simulation Model (Detail) (Series A Warrants [Member])	9 Months Ended
	Sep. 30, 2013
Series A Warrants [Member]	'
Class of Warrant or Right [Line Items]	'
Risk-free interest rate per year	0.70%
Expected volatility per year	83.60%
Expected dividend yield	0.00%
Expected life in years	'3 years 2 months 12 days

Warrant_Liability_Summary_of_C

Warrant Liability - Summary of Changes in Fair Value of Warrant Liability (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Class of Warrant or Right [Line Items]	'
Number of warrants, ending balance	9,601,378
Series A Warrants [Member]	'
Class of Warrant or Right [Line Items]	'
Number of warrants, beginning balance	8,501,429
Number of warrants exercised	-334,534
Number of warrants, ending balance	8,166,895
Fair value of warrant liability, beginning balance	$9,157,397
Fair value of warrants exercised	-418,841
Fair value, changes in fair value at period end	-332,862
Fair value of warrant liability, ending balance	$8,405,694

Warrant_Liability_Summary_of_O

Warrant Liability - Summary of Outstanding Warrants and Fair Value of Warrant Liability (Detail) (USD $)	Sep. 30, 2013
Class of Warrant or Right [Line Items]	'
Number Outstanding	9,601,378
Series A Warrants [Member]	'
Class of Warrant or Right [Line Items]	'
Number Outstanding	8,166,895
Exercise Price per share	1.4
November 2008 Financing [Member]	'
Class of Warrant or Right [Line Items]	'
Number Outstanding	1,034,483
Exercise Price per share	23
November 2009 Financing [Member]	'
Class of Warrant or Right [Line Items]	'
Number Outstanding	400,000
Exercise Price per share	15
Warrant liabilities [Member]	'
Class of Warrant or Right [Line Items]	'
Fair Value	8,420,954
Warrant liabilities [Member] | Series A Warrants [Member]	'
Class of Warrant or Right [Line Items]	'
Fair Value	8,405,694
Warrant liabilities [Member] | November 2008 Financing [Member]	'
Class of Warrant or Right [Line Items]	'
Fair Value	'
Warrant liabilities [Member] | November 2009 Financing [Member]	'
Class of Warrant or Right [Line Items]	'
Fair Value	15,260

Common_Stock_Additional_Inform

Common Stock - Additional Information (Detail) (USD $)

9 Months Ended

3 Months Ended

6 Months Ended

1 Months Ended

42 Months Ended

3 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

1 Months Ended

9 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Mar. 31, 2013

Jun. 30, 2013

Jun. 30, 2013

Jun. 30, 2009

Nov. 30, 2012

Mar. 31, 2013

Dec. 31, 2011

Mar. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Series A Warrants [Member]

Institutional Investors [Member]

Common Stock [Member]

2009 Sales Agreement [Member]

2009 Sales Agreement [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

2012 Amended Sales Agreement [Member]

2012 Amended Sales Agreement [Member]

2012 Amended Sales Agreement [Member]

Institutional Investors [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Subsidiary, Sale of Stock [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares available to sale

'

'

'

$30,000,000

'

$30,000,000

'

'

'

'

'

$30,000,000

'

'

Gross proceeds from common stock

6,115,442

16,196,587

'

3,000,000

'

'

26,700,000

'

'

'

'

'

3,317,000

'

Percentage of compensation paid to sales agent

'

'

'

'

'

'

'

'

'

'

'

'

3.00%

'

Common stock, sold

'

'

'

'

1,645,639

'

'

'

'

'

'

'

'

1,733,771

Sale of stock, price per share

'

'

'

'

$1.82

'

'

'

'

'

'

'

'

$1.91

Number of warrants exercised

'

'

'

'

'

'

'

334,534

'

'

'

'

'

'

Number of shares issued upon warrants exercise

'

'

'

'

329,131

'

'

'

'

334,534

2,700,000

'

'

'

Proceeds from sale of stock

'

'

468,000

'

'

'

'

468,000

468,000

'

'

'

'

'

Exercise period of rights

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

'

Additional amounts of common stock to sell

'

'

'

$27,000,000

'

'

'

'

'

'

'

'

'

'

Warrants termination agreement

'2013-10

'

'

'

'

'

'

'

'

'

'

'

'

'

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income - Summary of Changes in Accumulated Other Comprehensive Loss by Component (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Beginning balance	($35,090)	'	$193,177	'
Other comprehensive income before reclassifications	205,696	'	'	'
Amounts reclassified from accumulated other comprehensive loss	'	'	'	'
Other comprehensive income (loss)	205,695	99,293	-22,572	129,064
Ending balance	170,605	'	170,605	'
Unrealized Gain on Other Available-for-Sale Securities [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Beginning balance	425	'	'	'
Other comprehensive income before reclassifications	-425	'	'	'
Amounts reclassified from accumulated other comprehensive loss	'	'	'	'
Other comprehensive income (loss)	-425	'	'	'
Ending balance	'	'	'	'
Foreign Currency Translation [Member]	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'
Beginning balance	-35,515	'	'	'
Other comprehensive income before reclassifications	206,121	'	'	'
Amounts reclassified from accumulated other comprehensive loss	'	'	'	'
Other comprehensive income (loss)	206,121	'	'	'
Ending balance	$170,606	'	$170,606	'

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (USD $)

9 Months Ended

1 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2012

Nov. 30, 2008

Sep. 30, 2013

Oct. 31, 2013

Sep. 30, 2013

Oct. 31, 2013

Sep. 30, 2013

Oct. 31, 2013

Oct. 31, 2013

Sep. 30, 2013

Warrant liabilities [Member]

Series A Warrants [Member]

Subsequent Events [Member]

Subsequent Events [Member]

Subsequent Events [Member]

Subsequent Events [Member]

Subsequent Events [Member]

Subsequent Events [Member]

Subsequent Events [Member]

Warrant liabilities [Member]

Series A Warrants [Member]

Stem Cell Sciences (U.K.) Ltd [Member]

Common Stock [Member]

Common Stock [Member]

Patents

Subsequent Event [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares of common stock and warrants

'

'

'

'

'

12,845,500

'

'

'

'

'

'

Sale of common stock and warrant, price per share

'

'

'

'

'

$1.45

'

'

'

'

'

'

Proceeds from issuance of common stock and warrants

'

'

'

'

'

$17,300,000

'

'

'

'

'

'

Common stock, par value

$0.01

'

$0.01

'

'

$0.01

'

'

'

'

'

'

Number of shares of common stock or warrant in each unit sold to institutional investors

'

'

'

1

'

'

'

1

'

'

1

'

Number of securities callable by each warrant or right warrants

'

'

'

'

'

'

'

'

'

'

0.5

'

Warrant exercise price

'

'

'

'

1.4

1.8

'

'

1.4

'

'

'

Warrant expiration period

'

'

'

'

'

'5 years

'

'

'

'

'

'

Warrant exercise shares

'

'

'

'

'

'

'

'

50,000

'

'

'

Proceeds from the exercise of warrants

$460,097

$4,153,584

'

'

'

'

$70,000

'

'

'

'

'

Warrant common stock share issued

'

'

'

'

'

'

'

'

'

'

'

50,000

Number of patents acquired

'

'

'

'

'

'

'

'

'

6

'

'

Shares issued

329,131

'

'

'

'

'

'

'

'

139,548

'

'