Microbot Medical (MBOT) 10-K 13 Mar 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 24, 2015	Jun. 30, 2014
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Trading Symbol	STEM
Entity Registrant Name	STEMCELLS INC
Entity Central Index Key	883975
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		69,288,450
Entity Public Float			$113,248,184

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$24,987,603	$30,585,424
Trade receivables	159,466	108,815
Other receivables	256,166	486,222
Prepaid assets	1,017,726	530,037
Deferred financing costs, current	22,082	46,420
Other current assets	64,928	83,537
Total current assets	26,507,971	31,840,455
Property, plant and equipment, net	5,186,958	5,304,684
Other assets, non-current	373,717	413,717
Goodwill		2,139,294
Other intangible assets, net	356,889	1,835,717
Deferred financing costs, non-current	1,224	23,307
Total assets	32,426,759	41,557,174
Current liabilities:
Accounts payable	1,818,831	1,151,903
Accrued expenses and other current liabilities	4,869,710	4,067,916
Deferred revenue, current	16,826	67,245
Capital lease obligation, current	20,191	21,316
Deferred rent, current	85,925	34,366
Bonds payable, current		125,000
Loan payable net of discount, current	4,686,388	3,664,370
Total current liabilities	11,497,871	9,132,116
Capital lease obligation, non-current	9,230	29,422
Fair value of warrant liability	1,684,551	5,541,809
Other long-term liabilities	1,250,007	801,388
Loan payable net of discount, non-current	10,334,029	9,244,874
Deferred rent, non-current	1,734,214	1,790,943
Deferred revenue, non-current	46,084	62,910
Total liabilities	26,555,986	26,603,462
Commitments and contingencies (Note 12)
Stockholders' equity:
Common stock, $0.01 par value; 225,000,000 shares authorized; issued and outstanding 68,729,774 at December 31, 2014 and 55,138,311 at December 31, 2013	687,298	551,383
Additional paid-in capital	425,389,693	401,680,562
Accumulated deficit	-420,271,608	-387,530,334
Accumulated other comprehensive income	65,390	252,101
Total stockholders' equity	5,870,773	14,953,712
Total liabilities and stockholders' equity	$32,426,759	$41,557,174

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	225,000,000	225,000,000
Common stock, shares issued	68,729,774	55,138,311
Common stock, shares outstanding	68,729,774	55,138,311

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue:
Revenue from licensing agreements, grants and other	$1,012,391	$172,297	$489,717
Operating expenses:
Research and development	21,503,085	19,368,888	14,682,156
Selling, general and administrative	10,419,620	8,834,271	7,359,640
Wind-down expenses		61,837	356,379
Total operating expenses	31,922,705	28,264,996	22,398,175
Operating loss	-30,910,314	-28,092,699	-21,908,458
Other income (expense):
Change in fair value of warrant liability	2,422,451	3,253,253	-5,944,571
Impairment of goodwill	-1,910,062
Impairment of other intangible assets	-530,100
Interest income	8,532	11,318	15,594
Interest expense	-1,295,404	-1,166,782	-50,193
Other income (expense), net	-45,766	8,218	-83,631
Total other income (expense), net	-1,350,349	2,106,007	-6,062,801
Net loss from continuing operations	-32,260,663	-25,986,692	-27,971,259
Discontinued operations:
Loss from discontinued operations	-369,357	-452,467	-519,894
Net loss on disposal of assets	-111,254
Net loss from discontinued operations	-480,611	-452,467	-519,894
Net loss	($32,741,274)	($26,439,159)	($28,491,153)
Basic and diluted net loss per share:
Basic and diluted net loss per share from continuing operations	($0.52)	($0.60)	($0.97)
Basic and diluted net loss per share from discontinued operations	($0.01)	($0.01)	($0.02)
Basic and diluted net loss per share	($0.53)	($0.61)	($0.99)
Shares used to compute basic and diluted loss per share	61,612,957	43,422,001	28,824,417

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Loss (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net loss from continuing operations	($32,260,663)	($25,986,692)	($27,971,259)
Other comprehensive income (loss)
Unrealized gains (losses) on marketable securities		1,356	1,339
Comprehensive loss from continuing operations	-32,260,663	-25,985,336	-27,969,920
Discontinued operations:
Net loss from discontinued operations	-480,611	-452,467	-519,894
Other comprehensive income (loss)	-186,711	57,568	151,125
Comprehensive loss from discontinued operations	-667,322	-394,899	-368,769
Comprehensive loss	($32,927,985)	($26,380,235)	($28,338,689)

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance at Dec. 31, 2011	$10,725,124	$224,280	$343,060,153	($332,600,022)	$40,713
Beginning Balance, Shares at Dec. 31, 2011		22,427,955
Net loss	-28,491,153			-28,491,153
Unrealized gain on foreign currency translation	151,125				151,125
Change in unrealized loss on securities available-for-sale	1,339				1,339
Issuance of common stock and warrants, net of issuance cost of $900,992, $2,051,699 and $1,335,327 in 2012, 2013 and 2014 respectively	28,725,507	145,460	28,580,047
Issuance of common stock and warrants, net of issuance cost of $900,992, $2,051,699 and $1,335,327 in 2012, 2013 and 2014 respectively, Shares		14,546,042
Common stock issued for external services	175,235	1,021	174,214
Common stock issued for external services, shares		102,058
Common stock issued pursuant to employee benefit plan	97,017	1,299	95,718
Common stock issued pursuant to employee benefit plan, shares		129,893
Compensation expense from grant of options, restricted stock units and stock (fair value)	2,655,884	1,825	2,654,059
Compensation expense from grant of options, restricted stock units and stock (fair value), shares		182,502
Exercise of director stock options	3,629	36	3,593
Exercise of director stock options, shares	3,629	3,629
Exercise and net settlement of restricted stock units	-59,090	1,142	-60,232
Exercise and net settlement of restricted stock units, shares		114,226
Ending Balance at Dec. 31, 2012	13,984,617	375,063	374,507,552	-361,091,175	193,177
Ending Balance, Shares at Dec. 31, 2012		37,506,305
Net loss	-26,439,159			-26,439,159
Unrealized gain on foreign currency translation	57,568				57,568
Change in unrealized loss on securities available-for-sale	1,356				1,356
Issuance of common stock and warrants, net of issuance cost of $900,992, $2,051,699 and $1,335,327 in 2012, 2013 and 2014 respectively	24,879,573	169,385	24,710,188
Issuance of common stock and warrants, net of issuance cost of $900,992, $2,051,699 and $1,335,327 in 2012, 2013 and 2014 respectively, Shares		16,938,575
Common stock issued for external services	154,111	1,049	153,062
Common stock issued for external services, shares		104,911
Common stock issued pursuant to employee benefit plan	132,071	829	131,242
Common stock issued pursuant to employee benefit plan, shares		82,863
Compensation expense from grant of options, restricted stock units and stock (fair value)	2,322,489		2,322,489
Exercise of director stock options	3,452	35	3,417
Exercise of director stock options, shares	3,452	3,452
Exercise and net settlement of restricted stock units	-342,366	3,627	-345,993
Exercise and net settlement of restricted stock units, shares		362,657
Common stock issued as consideration in the acquisition of a patent portfolio	200,000	1,395	198,605
Common stock issued as consideration in the acquisition of a patent portfolio, shares		139,548
Ending Balance at Dec. 31, 2013	14,953,712	551,383	401,680,562	-387,530,334	252,101
Ending Balance, Shares at Dec. 31, 2013		55,138,311
Net loss	-32,741,274			-32,741,274
Unrealized gain on foreign currency translation	-186,711				-186,711
Issuance of common stock and warrants, net of issuance cost of $900,992, $2,051,699 and $1,335,327 in 2012, 2013 and 2014 respectively	22,359,386	128,522	22,230,864
Issuance of common stock and warrants, net of issuance cost of $900,992, $2,051,699 and $1,335,327 in 2012, 2013 and 2014 respectively, Shares		12,852,221
Common stock issued for external services	154,708	1,202	153,506
Common stock issued for external services, shares		120,149
Common stock issued pursuant to employee benefit plan	183,677	1,157	182,520
Common stock issued pursuant to employee benefit plan, shares		115,722
Compensation expense from grant of options, restricted stock units and stock (fair value)	1,646,608		1,646,608
Exercise of director stock options, shares	0
Exercise and net settlement of restricted stock units	-499,333	5,034	-504,367
Exercise and net settlement of restricted stock units, shares		503,371
Ending Balance at Dec. 31, 2014	$5,870,773	$687,298	$425,389,693	($420,271,608)	$65,390
Ending Balance, Shares at Dec. 31, 2014		68,729,774

Consolidated_Statement_of_Stoc1

Consolidated Statement of Stockholders' Equity (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Issuance cost on issuance of common stock and warrants	$1,335,327	$2,051,699	$900,992
Common Stock [Member]
Issuance cost on issuance of common stock and warrants	1,335,327	2,051,699	900,992
Additional Paid-in Capital [Member]
Issuance cost on issuance of common stock and warrants	$1,335,327	$2,051,699	$900,992

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net loss	($32,741,274)	($26,439,159)	($28,491,153)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,307,203	1,058,725	991,721
Amortization of debt discount and issuance costs	240,021	288,951
Stock-based compensation for employees and external services	2,034,898	2,608,670	2,878,134
Loss (gain) on disposal of fixed assets	-75,917	-38,854	20,883
Write-down of fixed assets			27,500
Impairment of intangible asset	530,100
Impairment of Goodwill	1,910,062
Loss on disposal of intangible assets relating to discontinued operations	186,846
Value of property gifted	5,671
Change in fair value of warrant liability	-2,422,451	-3,253,253	5,944,571
Changes in operating assets and liabilities:
Other receivables	192,795	-298,734	39,825
Trade receivables	-55,457	3,606	-50,451
Prepaid and other current assets	-465,478	801,611	22,232
Other assets	17,207	493,584	89,790
Accounts payable and accrued expenses	2,055,437	2,143,917	-409,333
Accrued wind-down expenses		-1,102,762	-1,032,024
Deferred revenue	-66,925	-24,270	13,389
Deferred rent	-5,169	435,967	85,572
Net cash used in operating activities	-27,352,431	-23,322,001	-19,869,344
Cash flows from investing activities:
Purchases of marketable debt securities		-687,798	-16,380,748
Sales or maturities of marketable debt securities		14,430,000	5,762,000
Purchases of property, plant and equipment	-903,943	-4,680,796	-73,083
Proceeds from sale of property, plant and equipment	3,500	38,500
Proceeds from the disposal of assets relating to discontinued operations	474,821
Acquisition of other assets		-64,000
Net cash provided by (used in) investing activities	-425,622	9,035,906	-10,691,831
Cash flows from financing activities:
Proceeds from issuance of common stock, net	18,949,647	23,491,597	19,747,550
Proceeds from the exercise of warrants	1,974,931	530,097	6,256,438
Proceeds from the exercise of stock options		3,452	3,629
Proceeds from loan payable, net of issuance costs	5,775,543	13,558,358
Payments related to net share issuance of stock based awards	-499,333	-342,366	-59,090
Repayments of capital lease obligations	-21,316	-12,396	-20,167
Repayments of debt obligations	-3,982,971	-826,465	-191,250
Net cash provided by financing activities	22,196,501	36,402,277	25,737,110
Increase (decrease) in cash and cash equivalents	-5,581,552	22,116,182	-4,824,065
Cash and cash equivalents at beginning of year	30,585,424	8,471,275	13,311,261
Effects of foreign currency rate changes on cash	-16,269	-2,033	-15,921
Cash and cash equivalents at end of the year	24,987,603	30,585,424	8,471,275
Supplemental disclosure of cash flow information:
Interest paid	479,011	427,040	50,193
Supplemental schedule of non-cash investing and financing activities:
Equipment acquired under a capital lease		43,600	21,721
Equity Financing Agreement [Member]
Supplemental schedule of non-cash investing and financing activities:
Fair value of shares issued as consideration		600,006
Acquired Patent Portfolio [Member]
Supplemental schedule of non-cash investing and financing activities:
Fair value of shares issued as consideration		$200,000

Consolidated_Statements_of_Cas1

Consolidated Statements of Cash Flows (Parenthetical) (USD $)	1 Months Ended
In Millions, except Share data, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2014
Equity Financing Agreement [Member]
Number of shares issued as consideration		329,131
Right to sell of common stock	$30
Acquired Patent Portfolio [Member]
Number of shares issued as consideration		139,548

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
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 cell-based therapeutics and related technologies.
	The accompanying consolidated financial statements have been prepared on the basis that we will continue as a going concern. Since inception, we have incurred annual losses and negative cash flows from operations and have an accumulated deficit of approximately $420 million at December 31, 2014. We have not derived significant revenue from the sale of products, and do not expect to receive significant revenue from product sales for at least several years. We may never be able to realize sufficient revenue to achieve or sustain profitability in the future.
	We expect to incur additional operating losses over the foreseeable future. We have limited liquidity and capital resources and must obtain significant additional capital and other resources in order to sustain our product development efforts, to provide funding for the acquisition of technologies and intellectual property rights, preclinical and clinical testing of our anticipated products, pursuit of regulatory approvals, acquisition of capital equipment, laboratory and office facilities, establishment of production capabilities, general and administrative expenses and other working capital requirements. We rely on our cash reserves, proceeds from equity and debt offerings, 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. Funding may not be available when needed — at all or on terms acceptable to us. 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 consolidated financial statements include the accounts of StemCells, Inc., and our wholly-owned subsidiaries, including StemCells California, Inc., Stem Cell Sciences Holdings Ltd (SCS), and Stem Cell Sciences (UK) Ltd (SCS UK). All significant intercompany accounts and transactions have been eliminated.
	Reclassifications
	Certain reclassifications have been made to the prior year financial statements in order to conform to the current year’s presentation.
	Use of Estimates
	The preparation of financial statements in conformity with generally accepted accounting principles requires management to make judgments, assumptions and estimates that affect the amounts reported in our consolidated financial statements and accompanying notes. Actual results could differ materially from those estimates.
	Significant estimates include the following:
		•		the fair value of share-based awards recognized as compensation (see Note 10, “Stock-Based Compensation”);
		•		valuation allowance against net deferred tax assets (see Note 18, “Income Taxes”);
		•		the fair value of warrants recorded as a liability (see Note 13, “Warrant Liability”); and
	Financial Instruments
	Cash Equivalents and Marketable Securities
	All money market and highly liquid investments with a maturity of 90 days or less at the date of purchase are classified as cash equivalents. Highly liquid investments with maturities of 365 days or less not previously classified as cash equivalents are classified as marketable securities, current. Investments with maturities greater than 365 days are classified as marketable securities, non-current.
	Trade and Other Receivables
	Our receivables generally consist of interest income on our financial instruments, revenue from licensing agreements and grants, revenue from product sales, and rent from our sub-lease tenants. Because dollar amounts for individual transactions related to our product sales are not material and because we have a broad customer base, we regard the associated credit risk to be minimal. In the fourth quarter of 2014, we sold and completed the wind down of our subsidiary SCS UK’s operations in Cambridge, UK which includes our SC Proven product line.
	Estimated Fair Value of Financial Instruments
	The estimated fair values of cash and cash equivalents, receivables and accounts payable approximates their carrying values due to the short maturities of these instruments.
	Property, Plant and Equipment
	Property, plant and equipment, including those held under capital lease, are stated at cost. Depreciation is computed by use of the straight-line method over the estimated useful lives of the assets, or the lease term if shorter, as follows:
	Building and improvements			3 - 20 years
	Machinery and equipment			3 - 10 years
	Furniture and fixtures			3 - 10 years
	Repairs and maintenance costs are expensed as incurred.
	Discontinued Operations
	The results of operations of a business that either has been disposed of or is classified as held-for-sale are reported in discontinued operations if the operations and cash flows of the component have been or will be eliminated from our ongoing operations as a result of the disposal transaction and we will not have any significant continuing involvement in the operations of the component after the disposal transaction. We present the operations of a business that meet this criteria as a discontinued operation, and retrospectively reclassify operating results for all prior periods presented. In the fourth quarter of 2014, as part of our strategy to focus on our clinical operations, we sold our SC Proven reagent and cell culture business and wound-down our business operations at our Subsidiary SCS UK in Cambridge, UK. The results of operations for this component have been classified as discontinued operations for all periods in our Consolidated Statement of Operations.
	Goodwill
	Goodwill is not amortized but subject to annual impairment tests. On April 1, 2009, we acquired the operations of SCS for an aggregate purchase price of approximately $5,135,000. Approximately 42% of the purchase price was allocated to Goodwill. The acquired operations included 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. In the fourth quarter of 2014, as part of our strategy to focus on our clinical operations, we sold our SC Proven reagent and cell culture business and wound-down our business operations at our Subsidiary SCS UK in Cambridge, UK. We also determined that we could not predict the future cash flows if any from the intellectual property portfolio acquired. Based on these factors, we determined that the Goodwill related to the acquisition was impaired and wrote off its carrying value of approximately $1,910,000.
	Intangible Assets (Patent and License Costs)
	Other intangible assets, net were approximately $357,000 at December 31, 2014. Intangible assets with finite useful lives are amortized generally on a straight-line basis over the periods benefited. Intangible assets deemed to have indefinite lives are not amortized but are subject to annual impairment tests. Intangible assets are also reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. 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 assays technology. Therefore, we determined that the intangible asset was impaired and wrote off the approximately $655,000 carrying value of the asset. Similarly, in December 2014, based on our decision to focus all of our efforts on moving our clinical programs forward, we determined we could not predict the future cash flows from the intangible IPR&D asset related to our Transgenic Rat Program and determined that the intangible asset was impaired and wrote off the approximately $530,000 carrying value of the asset.
	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 license agreement.
	Impairment of Long-Lived Tangible Assets
	Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. If property, plant, and equipment are considered to be impaired, the impairment to be recognized equals the amount by which the carrying value of the assets exceeds its estimated fair market value. In 2012, we recorded a charge of approximately $28,000 to adjust the fair value of certain lab equipment we expect to dispose. No such impairment was recognized during the year 2013 and 2014.
	Loan Payable
	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 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. 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. 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 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%.
	In April 2013, we entered into an agreement with the California Institute for Regenerative Medicine (CIRM) under which CIRM will provide up to approximately $19.3 million as a forgivable loan, in accordance with mutually agreed upon terms and conditions and CIRM regulations. The CIRM loan was to help fund preclinical development of our HuCNS-SC cells for Alzheimer’s disease. Between July 2013 and August 2014, we received in aggregate, approximately $9.6 million as disbursements of the loan provided under the CIRM Loan Agreement. However in December 2014, as findings under this pre-clinical study in Alzheimer’s disease did not meet pre-determined criteria for ongoing funding for this program by CIRM, we decided to wind down this pre-clinical study which had been funded in part by the CIRM loan agreement. Under the terms of the CIRM loan agreement, principal amount of approximately $8,917,000 and accrued interest of approximately $243,000 were forgiven. However, authoritative accounting guidance requires certain conditions (which includes a legal release from the creditor) to be met before a liability can be extinguished and derecognized. In February 2015, we repaid CIRM approximately $679,000 of the aggregate loan proceeds received.
	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. The 1,034,483 warrants issued as part of the November 2008 financing, expired unexercised by their own terms in May 2014. 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 2009, as well as the Series A 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 2009 financing is determined using the Black-Scholes-Merton (Black-Scholes) option pricing model and the fair value of the Series A Warrants is determined using a Monte Carlo simulation model (see Note 13, “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 December 31, 2014, was approximately $1,685,000.
	Revenue Recognition
	We recognize revenue resulting from licensing agreements, government grants, and product sales.
	Licensing agreements — We currently recognize revenue resulting from the licensing and use of our technology and intellectual property. Such licensing agreements may contain multiple elements, such as up-front fees, payments related to the achievement of particular milestones and royalties. Revenue from up-front 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.
	Government grants — 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.
	Product sales — We currently recognize revenue from the sale of products when the products are shipped, title to the products are transferred to the customer, when no further contingencies or material performance obligations are warranted, and thereby earning the right to receive reasonably assured payments for products sold and delivered. Cost of product sales includes labor, raw materials and shipping supplies. In the fourth quarter of 2014, we sold and completed the wind down of our subsidiary SCS UK’s operations in Cambridge, UK which includes our SC Proven product line. Product sales and its related costs are included in net loss from discontinued operations for all periods presented in our Consolidated Statement of Operations.
	Research and Development Costs
	Our research and development expenses consist primarily of salaries and related personnel expenses; costs associated with clinical trials and regulatory submissions; costs associated with preclinical activities such as toxicology studies; certain patent-related costs such as licensing; facilities-related costs such as depreciation; lab equipment and supplies. Clinical trial expenses include payments to vendors such as clinical research organizations, contract manufacturers, clinical trial sites, laboratories for testing clinical samples and consultants. All research and development costs are expensed as incurred.
	Stock-Based Compensation
	We expense the estimated fair value of our stock-based compensation awards. The estimated fair value is calculated using the Black-Scholes model. The compensation cost we record for these awards are based on their grant-date fair value as estimated and amortized over their vesting period. At the end of each reporting period we estimate forfeiture rates based on our historical experience within separate groups of employees and adjust stock-based compensation expense accordingly. See Note 10, “Stock-Based Compensation” for further information.
	Income Taxes
	When accounting for income taxes, we recognize deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the carrying amounts and the tax bases of assets and liabilities. Income tax receivables and liabilities and deferred tax assets and liabilities are recognized based on the amounts that more likely than not will be sustained upon ultimate settlement with taxing authorities.
	Developing our provision for income taxes and analyzing our uncertain tax positions requires significant judgment and knowledge of federal and state income tax laws, regulations and strategies, including the determination of deferred tax assets and liabilities and, any valuation allowances that may be required for deferred tax assets.
	We assess the realization of our deferred tax assets to determine whether an income tax valuation allowance is required. Based on such evidence that can be objectively verified, we determine whether it is more likely than not that all or a portion of the deferred tax assets will be realized. The main factors that we consider include:
		•		cumulative losses in recent years;
		•		income/losses expected in future years; and
		•		the applicable statute of limitations.
	Tax benefits associated with uncertain tax positions are recognized in the period in which one of the following conditions is satisfied: (1) the more likely than not recognition threshold is satisfied; (2) the position is ultimately settled through negotiation or litigation; or (3) the statute of limitations for the taxing authority to examine and challenge the position has expired. Tax benefits associated with an uncertain tax position are derecognized in the period in which the more likely than not recognition threshold is no longer satisfied.
	We concluded that the realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Accordingly, the net deferred tax assets have been fully offset by a valuation allowance. Deferred tax liabilities related to indefinite-lived assets that cannot be used as a source of taxable income to support the realization of deferred tax assets are reported as a net deferred tax liability.
	Net Loss per Share
	Basic net loss per share is computed based on the weighted-average number of shares of our common stock outstanding during the period. Diluted net loss per share is computed based on the weighted-average number of shares of our common stock and other dilutive securities.
	The following are the basic and dilutive net loss per share computations for the last three fiscal years:
			2014			2013			2012
Net loss from continuing operations		$	(32,260,663	)	$	(25,986,692	)	$	(27,971,259	)
Net loss from discontinued operations			(480,611	)		(452,467	)		(519,894	)
Net loss		$	(32,741,274	)	$	(26,439,159	)	$	(28,491,153	)
Weighted average shares outstanding used to compute basic and diluted net loss per share			61,612,957			43,422,001			28,824,417
Basic and diluted net loss per share from continuing operations		$	(0.52	)	$	(0.60	)	$	(0.97	)
Basic and diluted net loss per share from discontinued operations		$	(0.01	)	$	(0.01	)	$	(0.02	)
Basic and diluted net loss per share		$	(0.53	)	$	(0.61	)	$	(0.99	)
Outstanding options, warrants and restricted stock units were excluded from the computation of diluted net loss per share because the effect would have been anti-dilutive for all periods presented below:
		2014			2013			2012
Outstanding options			302,729			428,258			447,359
Restricted stock units			3,374,940			3,326,282			1,534,200
Outstanding warrants			23,478,181			16,267,659			9,935,912
Total			27,155,850			20,022,199			11,917,471
Comprehensive Income (Loss)
Comprehensive income (loss) is comprised of net losses and other comprehensive income (or “OCI”). OCI includes certain changes in stockholders’ equity that are excluded from net losses. Specifically, we include in OCI changes in unrealized gains and losses on our marketable securities and unrealized gains and losses on foreign currency translations.
The components of our accumulated OCI, as of December 31 of each year shown, are as follows:
		2014			2013
Unrealized gain on foreign currency translation		$	65,390		$	252,101
Recent Accounting Pronouncements
In August 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-15, “Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern,” to provide guidance on management’s responsibility in evaluating whether there is substantial doubt about a company’s ability to continue as a going concern and to provide related footnote disclosures. This update is effective for annual periods ending after December 15, 2016, and interim periods within annual periods beginning after December 15, 2016. Early application is permitted for annual or interim reporting periods for which the financial statements have not previously been issued. We do not expect the adoption of ASU 2014-15 to have a significant impact on our Consolidated Financial Statements or related disclosures.
In April 2014, the FASB issued ASU No. 2014-08, “Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity”. The amendments in ASU 2014-08 change the criteria for reporting discontinued operations while enhancing disclosures in this area. Under this guidance, only disposals representing a strategic shift in operations should be presented as discontinued operations. Those strategic shifts should have a major effect on the organization’s operations and financial results. This guidance is effective prospectively for all disposals of components of an entity that occur with annual periods beginning on or after December 15, 2014, and interim periods therein. We do not expect the adoption of ASU 2014-15 to have a significant impact on our Consolidated Financial Statements or related disclosures.

Financial_Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Financial Instruments	Note 2. Financial Instruments
	Cash, cash equivalents and marketable securities
	The following table summarizes the fair value of our cash and cash equivalents:
		Amortized		Gross		Gross		Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	December 31, 2014
	Cash	$	1,398,928	$	—	$	—	$	1,398,928
	Cash equivalents (money market accounts)		23,588,675		—		—		23,588,675
	Total cash, cash equivalents, and marketable securities	$	24,987,603	$	—	$	—	$	24,987,603
	December 31, 2013
	Cash	$	1,355,281	$	—	$	—	$	1,355,281
	Cash equivalents (money market accounts)		29,230,143		—		—		29,230,143
	Total cash, cash equivalents, and marketable securities	$	30,585,424	$	—	$	—	$	30,585,424
	At December 31, 2014, 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 December 31, 2014 includes approximately $652,000 held by our U.K. subsidiaries.
	We do not hold any investments that were in a material unrealized loss position as of December 31, 2014.

Fair_Value_Measurement

Fair Value Measurement	12 Months Ended
	Dec. 31, 2014
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 as of December 31, 2014 and 2013 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 were 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 our financial assets and liabilities measured at fair value as of December 31, 2014:
		Fair Value Measurement
		at Reporting Date Using
		Quoted Prices			Unobservable			As of
		in Active Markets for			Inputs			December 31,
		Identical Assets			(Level 3)			2014
		(Level 1)
	Financial assets
	Cash equivalents:
	Money market funds	$	421,418		$	—		$	421,418
	U.S. Treasury debt obligations		23,167,257			—			23,167,257
	Total financial assets	$	23,588,675		$	—		$	23,588,675
	Financial liabilities
	Loan payable net of discounts	$	—		$	15,020,417		$	15,020,417
	Warrant liabilities		—			1,684,551			1,684,551
	Total financial liabilities	$	—		$	16,704,968		$	16,704,968
	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 2014.
		Level 2			Settled			Level 2
		Beginning			$			Ending
		Balance 12/31/13						Balance 12/31/14
		$						$
	Bond obligation		125,000			(125,000	)		—
	Level 3 Reconciliation
	The following table presents a roll forward for liabilities measured at fair value using significant unobservable inputs (Level 3) for 2014.
		Warrant
		Liabilities
	Balance at December 31, 2013	$	5,541,809
	Less fair value of warrants exercised		(1,434,807	)
	Add change in fair value of warrants		(2,422,451	)
	Balance at December 31, 2014	$	1,684,551
		Loan
		Payable
	Balance at December 31, 2013	$	12,909,244
	Add loan proceeds		5,775,543
	Less repayments of principal		(3,857,971	)
	Add accretion of discount		193,601
	Balance at December 31, 2014	$	15,020,417
	Current portion	$	4,686,388
	Non-current portion		10,334,029
	Balance at December 31, 2014	$	15,020,417

Property_Plant_and_Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Note 4. Property, Plant and Equipment
	Property, plant and equipment balances at December 31 are summarized below:
		2014			2013
	Building and improvements	$	6,794,556		$	6,751,393
	Machinery and equipment		8,161,291			7,837,140
	Furniture and fixtures		639,909			602,599
			15,595,756			15,191,132
	Less accumulated depreciation and amortization		(10,408,798	)		(9,886,448	)
	Property, plant and equipment, net	$	5,186,958		$	5,304,684
	Depreciation and amortization expense was approximately $1,008,000 in 2014, $789,000 in 2013, and $728,000 in 2012.

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Note 5. Goodwill and Other Intangible Assets
	On April 1, 2009, we acquired the operations of SCS for an aggregate purchase price of approximately $5,135,000. The acquired operations included 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.
	At April 1, 2009, the purchase price was allocated as follows:
		Allocated			Estimated Life of
		Purchase			Intangible Assets
		Price			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 entire approximately $655,000 carrying value of the asset. Similarly, in December 2014, based on our decision to focus all of our efforts on moving our clinical programs forward, we determined we could not predict the future cash flows from the intangible IPR&D asset related to our Transgenic Rat Program and determined that the intangible asset was impaired and wrote off the approximately $530,000 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. In the fourth quarter of 2014, we sold and completed the wind down of our subsidiary SCS UK’s operations in Cambridge UK, which includes our SC Proven reagent and cell culture business. We received approximately $400,000 for certain business intellectual property rights, trademark and records related to the SC Proven product line.
	Approximately 42% of the purchase price was allocated to Goodwill. Goodwill is not amortized but subject to annual impairment tests. In the fourth quarter of 2014, as part of our strategy to focus on our clinical operations, we sold our SC Proven reagent and cell culture business and wound-down our business operations at our Subsidiary SCS UK in Cambridge, UK. We also determined that we could not predict the future cash flows if any from the intellectual property portfolio acquired. Based on these factors, we determined that the Goodwill related to the acquisition was impaired and wrote off its carrying value of approximately $1,910,000.
	The following table represents changes in goodwill in 2014:
	Balance as of December 31, 2013	$	2,139,294
	Net deferred tax liability related to indefinite lived IPR&D		(110,735	)
	Foreign currency translation		(118,497	)
	Impairment		(1,910,062	)
	Balance as of December 31, 2014	$	—
	The components of our other intangible assets at December 31, 2014 are summarized below:
	Other Intangible Asset Class	Cost			Accumulated			Proceeds			Foreign Currency		Write Off/			Net Carrying		Weighted-
					Amortization			from sale			Translation		Impairment			Amount		Average
																		Amortization
																		Period
	Related to SC Proven product line	$	1,620,000		$	(1,200,186	)	$	(400,000	)	$	167,038	$	(186,852	)	$	—		8.0 years
	In-process research and development		1,340,000			(270,687	)		—			115,748		(1,185,061	)		—		Indefinite
	Patents		1,243,612			(886,723	)		—			—		—			356,889		17.0 years
	Total other intangible assets	$	4,203,612		$	(2,357,596	)	$	(400,000	)	$	282,786	$	(1,371,913	)	$	356,889		11.9 years
	Amortization expense was approximately $299,000 in 2014, $269,000 in 2013, and $264,000 in 2012.
	The expected future annual amortization expense for each of the next five years based on current balances of our intangible assets is as follows:
	For the year ending December 31:
	2015	$	83,265
	2016	$	75,496
	2017	$	54,923
	2018	$	27,978
	2019	$	27,978

Other_Assets

Other Assets	12 Months Ended
	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	Note 6. Other Assets
	Other assets, non-current at December 31 are summarized below:
		2014		2013
	Security deposit (buildings and equipment lease)	$	373,717	$	413,717

Accounts_Payable

Accounts Payable	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Accounts Payable	Note 7. Accounts Payable
	Accounts payable at December 31 are summarized below:
		2014		2013
	External services	$	1,352,710	$	863,030
	Supplies		339,762		263,866
	Other		126,359		25,007
	Total accounts payable	$	1,818,831	$	1,151,903

Accrued_Expenses_and_Other_Cur

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Accrued Expenses and Other Current Liabilities	Note 8. Accrued Expenses and Other Current Liabilities
	Accrued expenses at December 31 are summarized below:
		2014		2013
	External services	$	2,152,770	$	1,191,048
	Employee compensation		2,415,826		2,655,242
	Other		301,114		221,626
	Total accrued expenses and other current liabilities	$	4,869,710	$	4,067,916

Other_LongTerm_Liabilities

Other Long-Term Liabilities	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Other Long-Term Liabilities	Note 9. Other Long-Term Liabilities
		2014		2013
	Accrued interest on loan payable	$	1,093,568	$	497,134
	Employee compensation		156,439		186,439
	Net deferred tax liability		—		117,815
	Total other long-term liabilities	$	1,250,007	$	801,388

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Note 10. Stock-Based Compensation
	We currently grant stock-based compensation under three equity incentive plans (2004, 2006 and 2013 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 December 31, 2014, we had 9,683,022 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. At our annual stockholders meeting held on December 20, 2013, our stockholders approved our 2013 Equity Incentive Plan to grant stock-based compensation of up to an initial 6,000,000 shares, plus an increase of 4% per year of the outstanding number of shares of our common stock beginning in January 1, 2015. Under the three 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.
	Generally, stock options and restricted stock units 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 and restricted stock units 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.
	Our stock-based compensation expense for the last three fiscal years was as follows:
			2014			2013			2012
	Research and development expense		$	608,840		$	1,219,308		$	1,280,298
	General and administrative expense			1,426,058			1,389,362			1,597,836
	Total stock-based compensation expense and effect on net loss		$	2,034,898		$	2,608,670		$	2,878,134
	As of December 31, 2014, we have approximately $3,262,000 of total unrecognized compensation expense related to unvested awards granted under our various share-based plans that we expect to recognize over a weighted-average period of 2.8 years.
	The fair value of stock options and restricted stock units granted is estimated as of the date of grant using the Black-Scholes option pricing model and expensed on a pro-rata straight-line basis over the period in which the stock options vest. The Black-Scholes option pricing model requires certain assumptions as of the date of grant. The weighted-average assumptions used for the last three fiscal years are as follows:
			2014			2013			2012
	Expected term (years)(1)			4.2			5.1			6.4
	Risk-free interest rate(2)			1.3	%		1.2	%		1.4	%
	Expected volatility(3)			78.7	%		89.3	%		78.4	%
	Expected dividend yield(4)			0	%		0	%		0	%
	-1	The expected term represents the period during which our stock-based awards are expected to be outstanding. We estimated this amount based on historical experience of similar awards, giving consideration to the contractual terms of the awards, vesting requirements, and expectation of future employee behavior, including post-vesting terminations.
	-2	The risk-free interest rate is based on U.S. Treasury debt securities with maturities close to the expected term of the option as of the date of grant.
	-3	Expected volatility is based on historical volatility over the most recent historical period equal to the length of the expected term of the option as of the date of grant.
	-4	We have neither declared nor paid dividends on any share of common stock and we do not expect to do so in the foreseeable future.
	At the end of each reporting period, we estimate forfeiture rates based on our historical experience within separate groups of employees and adjust the stock-based compensation expense accordingly.
	A summary of our stock option activity and related information for the last three fiscal years is as follows:
			Outstanding Options
			Number of			Weighted-			Weighted-Average			Aggregate
			Shares			Average			Remaining			Intrinsic
						Exercise Price			Contractual Term			Value(1)
	Balance at December 31, 2011			875,498		$	20.13			5.5		$	—
	Granted			—			—
	Exercised			(3,629	)	$	1					$	4,319
	Cancelled (forfeited and expired)			(424,510	)	$	20.86
	Balance at December 31, 2012			447,359		$	19.59			5.1		$	2,175
	Granted			—
	Exercised			(3,452	)	$	1					$	2,214
	Cancelled (forfeited and expired)			(15,649	)	$	13.06
	Balance at December 31, 2013			428,258		$	19.97			4.3		$	—
	Granted			—
	Exercised			—			—						—
	Cancelled (forfeited and expired)			(125,529	)	$	24.3
	Balance at December 31, 2014			302,729		$	18.18			3.3		$	—
	Exercisable at December 31, 2014			302,729		$	18.18			3.3		$	—
	Vested and expected to vest(2)			302,729		$	18.18			3.3		$	—
	-1	Aggregate intrinsic value represents the value of the closing price per share of our common stock on the last trading day of the fiscal period in excess of the exercise price multiplied by the number of options outstanding or exercisable, except for the “Exercised” line, which uses the closing price on the date exercised.
	-2	Number of shares includes options vested and those expected to vest net of estimated forfeitures.
	No options were granted in 2014, 2013 and 2012. Total intrinsic value of options exercised at time of exercise was approximately $2,000 in 2013 and $4,000 in 2012. No options were exercised in 2014.
	The following is a summary of changes in unvested options:
	Unvested Options		Number of			Weighted
			Options			Average
						Grant Date Fair
						Value
	Unvested options at December 31, 2013			18,466		$	8.11
	Granted			—			—
	Vested			(16,666	)	$	8.3
	Cancelled			(1,800	)	$	6.39
	Unvested options at December 31, 2014			—			—
	The estimated fair value of options vested were approximately $138,000 in 2014, $406,000 in 2013 and $627,000 in 2012.
	The following table presents weighted average exercise price and remaining term information about significant option groups outstanding at December 31, 2014:
	Options Outstanding at December 31, 2014
	Range of		Number			Weighted Average			Weighted Average			Aggregate Intrinsic
	Exercise Prices		Outstanding			Remaining			Exercise			Value at December 31,
						Term (Yrs.)			Price			2014
	Less than $10.00			300			5.5		$	8.9		$	—
	$10.00 - $19.99			170,170			4.4		$	11.85			—
	$20.00 - $29.99			107,959			2.1		$	23.24			—
	$30.00 - $39.99			17,800			1.1		$	36.7			—
	$40.00 - $49.99			4,500			0.7		$	47.89			—
$50.00 - $59.99			2,000			0.7		$	53.85			—
			302,729			3.3		$	18.18		$	—
Vested Options Outstanding at December 31, 2014
Range of Exercise Prices		Number			Weighted Average
		Outstanding			Exercise Price
Less than $10.00			300		$	8.9
$10.00 - $19.99			170,170		$	11.85
$20.00 - $29.99			107,959		$	23.24
$30.00 - $39.99			17,800		$	36.7
$40.00 - $49.99			4,500		$	47.89
$50.00 - $59.99			2,000		$	53.85
			302,729		$	18.18
Restricted Stock Units
We have granted restricted stock units (RSUs) to our directors and to certain employees which entitle the holders to receive shares of our common stock upon vesting of the RSUs. The fair value of restricted stock units granted are 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 our restricted stock unit activity for the year ended December 31, 2014 is as follows:
		Number of			Weighted Average
		RSUs			Grant Date Fair
					Value
Outstanding at January 1, 2014			3,326,282		$	1.68
Granted(1)			1,674,874		$	1.5
Vested and exercised			(851,216	)	$	1.71
Cancelled			(775,000	)	$	1.8
Outstanding at December 31, 2014			3,374,940		$	1.55
-1	228,874 of these restricted stock units vest and convert into shares of our common stock after one year from the date of grant. 150,000 of these restricted stock units vest and convert into shares of our common stock over a three year period from the date of grant: one-third of the award will vest on each grant date anniversary following the grant. 1,296,000 of these restricted stock units 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 December 31, 2014 are fully vested and there were no changes (grants, exercises or forfeitures) in the fourth quarter of 2014. 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.
For the year ended December 31, 2014, 2013 and 2012, the re-measured liability and compensation expense related to the SARs were not significant. The compensation expense recognized for the year ended December 31, 2014 and resulting effect on net loss and net loss per share attributable to common stockholders is not likely to be representative of the effects in future periods, 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_and_Exit_Costs

Wind-Down and Exit Costs	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Wind-Down and Exit Costs	Note 11. Wind-down and exit costs
	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 $854,000 at March 31, 2013. In 2013, payments net of subtenant income of approximately $916,000 were recorded against this reserve and approximately $62,000 as additional wind-down expenses. We have closed this reserve as the lease and our obligations related to it terminated on June 30, 2013.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 12. Commitments and Contingencies
	Bonds Payable
	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 a 21,000 square-foot pilot manufacturing facility and a 3,000 square-foot cell processing 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. In August 2014, we made the final principal and interest payment thereby extinguishing the debt and we are actively seeking to dispose these properties.
	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 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 $1,429,000 as of December 31, 2014, and approximately $1,434,000 as of December 31, 2013.
	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 $391,000 as of December 31, 2014, and December 31, 2013.
	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. The lease includes an option for early termination of the lease agreement. In December 2014, we sold our SC Proven reagent business and as part of the wind-down of our business operations in UK, sublet our leased space from January 2014 to our opted early termination date of October 2014.
	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.
	The table below summarizes the components of rent expense for the fiscal year ended December 31, as follows:
			2014		2013			2012
	Rent expense		$	1,955,747	$	2,612,899		$	2,932,104
	Sublease income			—		(53,726	)		(411,885	)
	Rent expense, net		$	1,955,747	$	2,559,173		$	2,520,219
	Future minimum payments under all leases and loan payable at December 31, 2014 are as follows:
			Loan1		Loan			Capital			Operating
			Payable CIRM		Payable SVB			Leases			Leases
	2015		$	679,166	$	4,322,035		$	21,591		$	1,981,461
	2016					1,440,678			9,454			1,968,459
	2017					—			—			2,014,706
	2018					—			—			2,061,260
	2019					—			—			2,108,130
	Thereafter					—			—			6,088,780
	Total minimum lease and loan payments			679,166		5,762,713			31,045		$	16,222,796
	Less amounts representing interest					240,899			1,624
	Principal amounts of bond payable, loan payable and capital lease obligations			679,166		5,521,814			29,421
	Less current maturities			679,166		4,099,319			20,191
	Bond payable, loan payable and capital lease obligations, less current maturities		$	—	$	1,422,495		$	9,230
	1	An aggregate of approximately $9.2 million of principal and accrued interest under the CIRM Loan Agreement is not included. In April 2013, we entered into an agreement with the CIRM under which CIRM will provide up to approximately $19.3 million as a forgivable loan, in accordance with mutually agreed upon terms and conditions and CIRM regulations. The CIRM loan was to help fund preclinical development of our HuCNS-SC cells for Alzheimer’s disease. Between July 2013 and August 2014, we received in aggregate, approximately $9.6 million as disbursements of the loan provided under the CIRM Loan Agreement. However in December 2014, as findings under this pre-clinical study in Alzheimer’s disease did not meet pre-determined criteria for ongoing funding for this program by CIRM, we decided to wind down this pre-clinical study which had been funded in part by the CIRM loan agreement. Under the terms of the CIRM loan agreement, principal amount of approximately $8,917,000 and accrued interest of approximately $243,000 were forgiven. However, authoritative accounting guidance requires certain conditions (which includes a legal release from the creditor) to be met before a liability can be extinguished and derecognized. In February 2015, we repaid CIRM approximately $679,000 of the aggregate loan proceeds received.
	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 at the time from 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 licensed at the time 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. Fact discovery has concluded in the cases and in December 2014, the Maryland federal court began the first phase of trial in order to address the sole question of whether we have legal standing to pursue our patent infringement claims against Neuralstem. We expect a ruling on the question of standing in the first half of 2015.
	In addition to the actions described above, in April 2008, we filed an opposition to Neuralstem’s European Patent No. 0 915 968 (methods of isolating, propagating and differentiating CNS stem cells), because the claimed invention is believed by us to be unpatentable over prior art, including the patents we acquired from NeuroSpheres. In December 2010, the European Patent Office ruled that all composition claims in Neuralstem’s ‘968 European patent were invalid and unpatentable over prior art including several of the NeuroSpheres patents. Neuralstem appealed this decision but subsequently withdrew its appeal with prejudice.

Warrant_Liability

Warrant Liability	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Warrant Liability	Note 13. 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 consolidated statements of operations. The November 2008 warrants expired unexercised by their own terms in May 2014.
	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 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 fair value of these warrants at December 31, 2014 was not significant.
	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, 2013 and 2014, an aggregate of 2,198,571, 384,534 and 1,180,015 Series A Warrants were exercised, respectively. For the exercise of these warrants, in 2012, 2013 and 2014, we issued 2,198,571, 384,534 and 1,180,015 shares of our common stock and received gross proceeds of approximately $3,078,000, $538,000 and $1,652,000, respectively. The shares were offered under our shelf registration statement previously filed with previously filed with, and declared effective by, the SEC.
	The fair value of the warrant liability will be 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 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 Monte Carlo simulation model to value the outstanding Series A Warrants at December 31, 2014 are as follows:
	Risk-free interest rate per year		0.7	%
	Expected volatility per year		53.4	%
	Expected dividend yield		0	%
	Expected life (years)		2
	The use of the 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 in 2014:
		Series A
		Number of			Fair value $
		Warrants
	Balance at December 31, 2013		8,116,895		$	5,541,809
	Less exercised		(1,180,015	)		(1,434,807	)
	Changes in fair value		—			(2,422,451	)
	Balance at December 31, 2014		6,936,880		$	1,684,551
	The following table is a summary of our warrant liability as of December 31, 2014:
	Warrants	Number Outstanding			Exercise Price ($)			Fair value
					per share
	Warrants issued in 2009		400,000			15			—
	Series A Warrants		6,936,880			1.4			1,684,551
	Total		7,336,880					$	1,684,551

Loan_Payable

Loan Payable	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Loan Payable	Note 14. 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 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 CIRM under which CIRM will provide up to approximately $19.3 million as a forgivable loan, in accordance with mutually agreed upon terms and conditions and CIRM regulations. The CIRM loan was to help fund preclinical development of our HuCNS-SC cells for Alzheimer’s disease. Between July 2013 and August 2014, we received in aggregate, approximately $9.6 million as disbursements of the loan provided under the CIRM Loan Agreement. However in December 2014, as findings under this pre-clinical study in Alzheimer’s disease did not meet pre-determined criteria for ongoing funding for this program by CIRM, we decided to wind down this pre-clinical study which had been funded in part by the CIRM loan agreement. Under the terms of the CIRM loan agreement, principal amount of approximately $8,917,000 and accrued interest of approximately $243,000 were forgiven. However, authoritative accounting guidance requires certain conditions (which includes a legal release from the creditor) to be met before a liability can be extinguished and derecognized. In February 2015, we repaid CIRM approximately $679,000 of the aggregate loan proceeds received.
	The following table is a summary of the changes in the carrying value of our loan payable in 2014:
		Silicon Valley			CIRM Loan		Total
		Bank Loan
	Loan payable at December 31, 2013	$	9,088,980		$	3,820,264	$	12,909,244
	Additional loan proceeds		—			5,775,543		5,775,543
	Repayment of principal		(3,857,971	)		—		(3,857,971	)
	Accretion of discount		193,601			—		193,601
	Carrying value of loan payable at 12/31/2014 (current and non-current)	$	5,424,610		$	9,595,807	$	15,020,417
	Carrying value of loan payable, current portion	$	4,007,222		$	679,166	$	4,686,388
	Carrying value of loan payable, non-current portion		1,417,388			8,916,641		10,334,029
	Total loan payable at December 31, 2014	$	5,424,610		$	9,595,807	$	15,020,417

Common_Stock

Common Stock	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Common Stock	Note 15. Common Stock
	Sale of common stock
	Major transactions involving our common stock for the last three years include the following:
		•	In July 2014, we raised gross proceeds of $20,000,000 through the sale of 11,299,435 units to two institutional biotechnology investors, at an offering price of $1.77 per unit. Each unit consists of one share of our common stock and a warrant to purchase 0.85 of a share of our common stock. The warrants are exercisable six months from the date of issuance at an exercise price of $2.17. The Warrants are non-transferable and will expire thirteen months from the date of issuance. The shares were offered under our shelf registration statement previously filed with, and declared effective by, the SEC.
		•	In 2014, an aggregate of 1,180,015 Series A Warrants were exercised. For the exercise of these warrants, we issued 1,180,015 shares of our common stock and received gross proceeds of approximately $1,652,000.
		•	Under a sales agreement entered into in 2009 and amended in 2012, we have the option to sell up to $30 million of our common stock from time to time, in at-the-market offerings. The sales agent is paid compensation of 2% of gross proceeds pursuant to the terms of the amended agreement. The sales agreement as amended, has been filed with the SEC. Under the amended sales agreement, in 2014, we sold a total of 193,271 shares of our common stock at an average price per share of $1.47 for gross proceeds of approximately $285,000. The shares were offered under our shelf registration statement previously filed with, and declared effective by, the SEC.
		•	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.
		•	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.
		•	In 2013, we sold an aggregate 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. These sales were made under a sales agreement entered into in June 2009 (2009 sales agreement) and the sales agent was paid compensation equal to 3% of gross proceeds pursuant to the terms of the agreement. The shares were offered under our shelf registration statement previously filed with, and declared effective by, the SEC.
		•	In 2013, an aggregate of 384,534 Series A Warrants were exercised. For the exercise of these warrants, we issued 384,534 shares of our common stock and received gross proceeds of approximately $538,000.
		•	In 2012, we sold an aggregate of 9,647,471 shares of our common stock at an average price per share of $2.12 for gross proceeds of approximately $20,452,000. These sales were made under the 2009 sales agreement and the sales agent was paid compensation equal to 3% of gross proceeds pursuant to the terms of the agreement. The shares were offered under our shelf registration statement previously filed with, and declared effective by, the SEC.
		•	In 2012, an aggregate of 2,700,000 Series B Warrants were exercised and we received gross proceeds of $3,375,000. The remaining 5,300,000 Series B Warrants expired unexercised by their terms on May 2, 2012. For the exercise of these warrants, we issued 2,700,000 shares of our common stock and 2,700,000 Series A Warrants.
		•	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 and received gross proceeds of approximately $3,078,000.
	Common Stock Reserved
	We reserved the following shares of common stock for the exercise of options, warrants and other contingent issuances of common stock, as of December 31, 2014:
	Shares reserved for share based compensation		13,360,690
	Shares reserved for warrants related to financing transactions		23,078,181
	Total		36,438,871

Deferred_Revenue

Deferred Revenue	12 Months Ended
	Dec. 31, 2014
Deferred Revenue Disclosure [Abstract]
Deferred Revenue	Note 16. Deferred Revenue
	Deferred revenue includes unamortized upfront licensing fees received of approximately $63,000. The up-front license fee is being amortized and recognized as revenue over a period of twelve years.

401k_Plan

401(k) Plan	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
401(k) Plan	Note 17. 401(k) Plan
	Our 401(k) Plan covers substantially all of our employees. Participants in the plan are permitted to contribute a fixed percentage of their total annual cash compensation to the plan (subject to the maximum employee contribution defined by law). We match 50% of employee contributions, up to a maximum of 6% of each employee’s eligible compensation in the form of shares of our common stock. We recorded an expense of $184,000 in 2014, $132,000 in 2013, and $130,000 in 2012 for our contributions under our 401(k) Plan.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income Taxes	Note 18. Income Taxes
	Loss before income taxes is attributed to the following geographic locations for the years ended December 31,
			2014			2013
	United States		$	30,215,000		$	26,080,000
	Foreign			2,526,000			359,000
	Total loss before income taxes		$	32,741,000		$	26,439,000
	We follow authoritative guidance regarding accounting for uncertainty in income taxes, which prescribes a recognition threshold a tax position is required to meet before being recognized in the financial statements. As of December 31, 2014 and 2012, we have not recorded any unrecognized tax benefits. Deferred income taxes reflect the tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our deferred tax assets and liabilities at December 31 are as follows:
			2014			2013
	Deferred tax assets:
	Capitalized research and development costs		$	66,212,000		$	59,426,000
	Net operating losses			57,261,000			56,906,000
	Research and development credits			9,798,000			8,931,000
	Stock-based compensation			1,124,000			1,063,000
	Capital loss carryover			254,000			541,000
	Fixed assets			393,000			452,000
	Other			3,930,000			1,289,000
				138,972,000			128,608,000
	Valuation allowance			(138,972,000	)		(128,315,000	)
	Total deferred tax assets		$	—		$	293,000
	Deferred tax liability:
	Intangible assets			—			(293,000	)
	Total deferred tax liability		$	—		$	(293,000	)
	Net deferred tax assets		$	—		$	—
	Realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Accordingly, the net deferred tax assets have been fully offset by a valuation allowance. The valuation allowance increased by approximately $10,657,000 in 2014 and by approximately $10,270,000 in 2013.
	As of December 31, 2014, we had the following:
		•		Net operating loss carry forwards for federal income tax purposes of approximately $158,465,000 which expire in the years 2018 through 2034. This includes $1,792,000 of excess deductions from the exercise of stock options, the benefit of which will be recorded in additional paid-in-capital when realized
		•		Federal research and development tax credits of approximately $6,178,000 which expire in the years 2018 through 2034.
		•		Net operating loss carry forwards for state income tax purposes of approximately $40,241,000 which expire in the years 2015 through 2034. This includes $1,362,000 of excess deductions from the exercise of stock options, the benefit of which will be recorded in additional paid-in-capital when realized.
		•		State research and development tax credits of approximately $5,484,000 ($3,619,000 net of federal tax effect) which do not expire.
		•		Net operating loss carry forwards in foreign jurisdictions of approximately $8,208,000 which do not expire.
		•		Capital loss carry forwards for federal and state income tax purposes of $746,000 which expire in the years 2015 through 2016.
	Utilization of the federal and state net operating loss and federal and state research and development tax credit carry forwards may be subject to annual limitations due to the ownership percentage change provisions of the Internal Revenue Code of 1986 and similar state provisions. The annual limitations may result in the inability to fully offset future annual taxable income and could result in the expiration of the net operating loss carry forwards before utilization. Utilization of foreign net operating loss carry forwards may be limited or disallowed under similar foreign income tax provisions.
	The effective tax rate as a percentage of income before income taxes differs from the statutory federal income tax rate (when applied to income before income taxes) for the years ended December 31 as follows:
			2014			2013			2012
	Statutory federal income tax (benefit) rate			(34	)%		(34	)%		(34	)%
	State income tax (benefit) rate			—			—			(3.3	)
	Increase resulting from:
	Expenses not deductible for taxes			0.8			0.5			8.8
	Increase in valuation allowance			32.6			38.8			3.7
	Change in state deferred tax rate			0			1.1			17.7
	Change in foreign deferred tax rate			2.8			0.9			1.8
	Expiration of tax attributes			1.7			0.5			5.3
	Prior year true up			1.1			(0.7	)		—
	Tax credits			(2.4	)		(3.0	)		—
	Warrant valuation			(2.5	)		(4.1	)		—
	Effective tax (benefit) rate			0	%		0	%		0	%
	We did not have any unrecognized tax benefits at December 31, 2014. Our policy is to recognize interest and penalties related to income tax matters in income tax expense. Because we have no tax liabilities, no tax-related interest and penalties have been expensed in our consolidated statements of operations during 2014 or accrued as a liability in our consolidated balance sheets at December 31, 2014. We do not anticipate any significant changes to total unrecognized tax benefits as a result of settlement of audits or the expiration of statute of limitations within the next twelve months.
	We file U.S. federal income tax returns, as well as tax returns with the State of California and the State of Rhode Island. Due to the carry forward of unutilized net operating losses and research and development credits, our federal tax returns from 1998 forward remain subject to examination by the Internal Revenue Service, and our State of California tax returns from 2001 forward and our State of Rhode Island tax returns from 2009 forward remain subject to examination by the respective state tax authorities. We file income tax returns in various foreign jurisdictions. Tax years from 2007 forward remain subject to examination by the appropriate foreign governmental agencies.

Discontinued_Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations	Note 19. Discontinued Operations
	In the fourth quarter of 2014, we sold and completed the wind down of our subsidiary SCS UK’s operations in Cambridge, UK, which includes the SC Proven reagent and cell culture business. We classified the historical results of this component as discontinued operations in our Consolidated Statement of Operations. At December 31, 2014, the remaining assets and liabilities of the discontinued operations included in our Consolidated Balance Sheets are not significant.
	From the sale and wind-down of our SC Proven reagent and cell culture business, we received approximately $400,000 for certain business intellectual property rights, trade mark and records and approximately $75,000 for tangible assets. For the disposal of these assets, we recorded a net loss on disposal of assets of approximately $111,000 in our Consolidated Statement of Operations.
	As a result of the disposition, we are no longer in the businesses of marketing and selling specialized cell culture products and antibody reagents through the SC Proven product line.

Quarterly_Financial_Data

Quarterly Financial Data	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Data	QUARTERLY FINANCIAL DATA (unaudited)
		2014 Quarter Ended
		December 31			September 30			June 30			March 31
		(In $ thousands, except per share amounts)
	Continuing operations:
	Total revenue		883			82			23			24
	Operating expenses		10,612			6,462			7,983			6,866
	Change in fair value of warrant liability		2,327			4,076			(3,654	)		(327	)
	Impairment of goodwill and other intangible assets		(2,440	)		—			—			—
	Interest and other expense, net		(266	)		(316	)		(357	)		(394	)
	Net loss from continuing operations		(10,108	)		(2,620	)		(11,971	)		(7,562	)
	Discontinued operations:
	Net loss from discontinued operations		(30	)		(137	)		(144	)		(58	)
	Net loss from disposal of assets		(111	)		—			—			—
	Basic and diluted net loss per share:
	Continuing operations	$	(0.15	)	$	(0.04	)	$	(0.21	)	$	(0.14	)
	Discontinued operations	$	(0.00	)	$	(0.00	)	$	(0.00	)	$	(0.00	)
	Basic and diluted net loss per share	$	(0.15	)	$	(0.04	)	$	(0.21	)	$	(0.14	)
		2013 Quarter Ended
		December 31			September 30			June 30			March 31
		(In thousands, except per share amounts)
	Continuing operations:
	Total revenue		45			38			33			56
	Operating expenses		9,341			6,628			6,131			6,165
	Change in fair value of warrant liability		2,828			(144	)		758			(189	)
	Interest and other income (expense), net		(380	)		(392	)		(405	)		30
	Net loss from continuing operations		(6,848	)		(7,126	)		(5,745	)		(6,268	)
	Discontinued operations:
	Net loss from discontinued operations		(115	)		(66	)		(124	)		(149	)
	Basic and diluted net loss per share:
	Continuing operations	$	(0.13	)	$	(0.17	)	$	(0.14	)	$	(0.16	)
	Discontinued operations	$	(0.00	)	$	(0.00	)	$	(0.01	)	$	(0.01	)
	Basic and diluted net loss per share	$	(0.13	)	$	(0.17	)	$	(0.15	)	$	(0.17	)

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
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 cell-based therapeutics and related technologies.
	The accompanying consolidated financial statements have been prepared on the basis that we will continue as a going concern. Since inception, we have incurred annual losses and negative cash flows from operations and have an accumulated deficit of approximately $420 million at December 31, 2014. We have not derived significant revenue from the sale of products, and do not expect to receive significant revenue from product sales for at least several years. We may never be able to realize sufficient revenue to achieve or sustain profitability in the future.
	We expect to incur additional operating losses over the foreseeable future. We have limited liquidity and capital resources and must obtain significant additional capital and other resources in order to sustain our product development efforts, to provide funding for the acquisition of technologies and intellectual property rights, preclinical and clinical testing of our anticipated products, pursuit of regulatory approvals, acquisition of capital equipment, laboratory and office facilities, establishment of production capabilities, general and administrative expenses and other working capital requirements. We rely on our cash reserves, proceeds from equity and debt offerings, 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. Funding may not be available when needed — at all or on terms acceptable to us. 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 consolidated financial statements include the accounts of StemCells, Inc., and our wholly-owned subsidiaries, including StemCells California, Inc., Stem Cell Sciences Holdings Ltd (SCS), and Stem Cell Sciences (UK) Ltd (SCS UK). All significant intercompany accounts and transactions have been eliminated.
Reclassifications	Reclassifications
	Certain reclassifications have been made to the prior year financial statements in order to conform to the current year’s presentation.
Use of Estimates	Use of Estimates
	The preparation of financial statements in conformity with generally accepted accounting principles requires management to make judgments, assumptions and estimates that affect the amounts reported in our consolidated financial statements and accompanying notes. Actual results could differ materially from those estimates.
	Significant estimates include the following:
		•		the fair value of share-based awards recognized as compensation (see Note 10, “Stock-Based Compensation”);
		•		valuation allowance against net deferred tax assets (see Note 18, “Income Taxes”);
		•		the fair value of warrants recorded as a liability (see Note 13, “Warrant Liability”); and
Financial Instruments	Financial Instruments
	Cash Equivalents and Marketable Securities
	All money market and highly liquid investments with a maturity of 90 days or less at the date of purchase are classified as cash equivalents. Highly liquid investments with maturities of 365 days or less not previously classified as cash equivalents are classified as marketable securities, current. Investments with maturities greater than 365 days are classified as marketable securities, non-current.
	Trade and Other Receivables
	Our receivables generally consist of interest income on our financial instruments, revenue from licensing agreements and grants, revenue from product sales, and rent from our sub-lease tenants. Because dollar amounts for individual transactions related to our product sales are not material and because we have a broad customer base, we regard the associated credit risk to be minimal. In the fourth quarter of 2014, we sold and completed the wind down of our subsidiary SCS UK’s operations in Cambridge, UK which includes our SC Proven product line.
Estimated Fair Value of Financial Instruments	Estimated Fair Value of Financial Instruments
	The estimated fair values of cash and cash equivalents, receivables and accounts payable approximates their carrying values due to the short maturities of these instruments.
Property, Plant and Equipment	Property, Plant and Equipment
	Property, plant and equipment, including those held under capital lease, are stated at cost. Depreciation is computed by use of the straight-line method over the estimated useful lives of the assets, or the lease term if shorter, as follows:
	Building and improvements			3 - 20 years
	Machinery and equipment			3 - 10 years
	Furniture and fixtures			3 - 10 years
	Repairs and maintenance costs are expensed as incurred.
Discontinued Operations	Discontinued Operations
	The results of operations of a business that either has been disposed of or is classified as held-for-sale are reported in discontinued operations if the operations and cash flows of the component have been or will be eliminated from our ongoing operations as a result of the disposal transaction and we will not have any significant continuing involvement in the operations of the component after the disposal transaction. We present the operations of a business that meet this criteria as a discontinued operation, and retrospectively reclassify operating results for all prior periods presented. In the fourth quarter of 2014, as part of our strategy to focus on our clinical operations, we sold our SC Proven reagent and cell culture business and wound-down our business operations at our Subsidiary SCS UK in Cambridge, UK. The results of operations for this component have been classified as discontinued operations for all periods in our Consolidated Statement of Operations.
Goodwill	Goodwill
	Goodwill is not amortized but subject to annual impairment tests. On April 1, 2009, we acquired the operations of SCS for an aggregate purchase price of approximately $5,135,000. Approximately 42% of the purchase price was allocated to Goodwill. The acquired operations included 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. In the fourth quarter of 2014, as part of our strategy to focus on our clinical operations, we sold our SC Proven reagent and cell culture business and wound-down our business operations at our Subsidiary SCS UK in Cambridge, UK. We also determined that we could not predict the future cash flows if any from the intellectual property portfolio acquired. Based on these factors, we determined that the Goodwill related to the acquisition was impaired and wrote off its carrying value of approximately $1,910,000.
Intangible Assets (Patent and License Costs)	Intangible Assets (Patent and License Costs)
	Other intangible assets, net were approximately $357,000 at December 31, 2014. Intangible assets with finite useful lives are amortized generally on a straight-line basis over the periods benefited. Intangible assets deemed to have indefinite lives are not amortized but are subject to annual impairment tests. Intangible assets are also reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. 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 assays technology. Therefore, we determined that the intangible asset was impaired and wrote off the approximately $655,000 carrying value of the asset. Similarly, in December 2014, based on our decision to focus all of our efforts on moving our clinical programs forward, we determined we could not predict the future cash flows from the intangible IPR&D asset related to our Transgenic Rat Program and determined that the intangible asset was impaired and wrote off the approximately $530,000 carrying value of the asset.
	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 license agreement.
Impairment of Long-Lived Tangible Assets	Impairment of Long-Lived Tangible Assets
	Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. If property, plant, and equipment are considered to be impaired, the impairment to be recognized equals the amount by which the carrying value of the assets exceeds its estimated fair market value. In 2012, we recorded a charge of approximately $28,000 to adjust the fair value of certain lab equipment we expect to dispose. No such impairment was recognized during the year 2013 and 2014.
Loan Payable	Loan Payable
	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 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. 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. 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 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%.
	In April 2013, we entered into an agreement with the California Institute for Regenerative Medicine (CIRM) under which CIRM will provide up to approximately $19.3 million as a forgivable loan, in accordance with mutually agreed upon terms and conditions and CIRM regulations. The CIRM loan was to help fund preclinical development of our HuCNS-SC cells for Alzheimer’s disease. Between July 2013 and August 2014, we received in aggregate, approximately $9.6 million as disbursements of the loan provided under the CIRM Loan Agreement. However in December 2014, as findings under this pre-clinical study in Alzheimer’s disease did not meet pre-determined criteria for ongoing funding for this program by CIRM, we decided to wind down this pre-clinical study which had been funded in part by the CIRM loan agreement. Under the terms of the CIRM loan agreement, principal amount of approximately $8,917,000 and accrued interest of approximately $243,000 were forgiven. However, authoritative accounting guidance requires certain conditions (which includes a legal release from the creditor) to be met before a liability can be extinguished and derecognized. In February 2015, we repaid CIRM approximately $679,000 of the aggregate loan proceeds received.
Warrant Liability	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. The 1,034,483 warrants issued as part of the November 2008 financing, expired unexercised by their own terms in May 2014. 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 2009, as well as the Series A 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 2009 financing is determined using the Black-Scholes-Merton (Black-Scholes) option pricing model and the fair value of the Series A Warrants is determined using a Monte Carlo simulation model (see Note 13, “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 December 31, 2014, was approximately $1,685,000.
Revenue Recognition	Revenue Recognition
	We recognize revenue resulting from licensing agreements, government grants, and product sales.
	Licensing agreements — We currently recognize revenue resulting from the licensing and use of our technology and intellectual property. Such licensing agreements may contain multiple elements, such as up-front fees, payments related to the achievement of particular milestones and royalties. Revenue from up-front 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.
	Government grants — 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.
	Product sales — We currently recognize revenue from the sale of products when the products are shipped, title to the products are transferred to the customer, when no further contingencies or material performance obligations are warranted, and thereby earning the right to receive reasonably assured payments for products sold and delivered. Cost of product sales includes labor, raw materials and shipping supplies. In the fourth quarter of 2014, we sold and completed the wind down of our subsidiary SCS UK’s operations in Cambridge, UK which includes our SC Proven product line. Product sales and its related costs are included in net loss from discontinued operations for all periods presented in our Consolidated Statement of Operations.
Research and Development Costs	Research and Development Costs
	Our research and development expenses consist primarily of salaries and related personnel expenses; costs associated with clinical trials and regulatory submissions; costs associated with preclinical activities such as toxicology studies; certain patent-related costs such as licensing; facilities-related costs such as depreciation; lab equipment and supplies. Clinical trial expenses include payments to vendors such as clinical research organizations, contract manufacturers, clinical trial sites, laboratories for testing clinical samples and consultants. All research and development costs are expensed as incurred.
Stock-Based Compensation	Stock-Based Compensation
	We expense the estimated fair value of our stock-based compensation awards. The estimated fair value is calculated using the Black-Scholes model. The compensation cost we record for these awards are based on their grant-date fair value as estimated and amortized over their vesting period. At the end of each reporting period we estimate forfeiture rates based on our historical experience within separate groups of employees and adjust stock-based compensation expense accordingly. See Note 10, “Stock-Based Compensation” for further information.
Income Taxes	Income Taxes
	When accounting for income taxes, we recognize deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the carrying amounts and the tax bases of assets and liabilities. Income tax receivables and liabilities and deferred tax assets and liabilities are recognized based on the amounts that more likely than not will be sustained upon ultimate settlement with taxing authorities.
	Developing our provision for income taxes and analyzing our uncertain tax positions requires significant judgment and knowledge of federal and state income tax laws, regulations and strategies, including the determination of deferred tax assets and liabilities and, any valuation allowances that may be required for deferred tax assets.
	We assess the realization of our deferred tax assets to determine whether an income tax valuation allowance is required. Based on such evidence that can be objectively verified, we determine whether it is more likely than not that all or a portion of the deferred tax assets will be realized. The main factors that we consider include:
		•		cumulative losses in recent years;
		•		income/losses expected in future years; and
		•		the applicable statute of limitations.
	Tax benefits associated with uncertain tax positions are recognized in the period in which one of the following conditions is satisfied: (1) the more likely than not recognition threshold is satisfied; (2) the position is ultimately settled through negotiation or litigation; or (3) the statute of limitations for the taxing authority to examine and challenge the position has expired. Tax benefits associated with an uncertain tax position are derecognized in the period in which the more likely than not recognition threshold is no longer satisfied.
	We concluded that the realization of deferred tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Accordingly, the net deferred tax assets have been fully offset by a valuation allowance. Deferred tax liabilities related to indefinite-lived assets that cannot be used as a source of taxable income to support the realization of deferred tax assets are reported as a net deferred tax liability.
Net Loss per Share	Net Loss per Share
	Basic net loss per share is computed based on the weighted-average number of shares of our common stock outstanding during the period. Diluted net loss per share is computed based on the weighted-average number of shares of our common stock and other dilutive securities.
	The following are the basic and dilutive net loss per share computations for the last three fiscal years:
			2014			2013			2012
	Net loss from continuing operations		$	(32,260,663	)	$	(25,986,692	)	$	(27,971,259	)
	Net loss from discontinued operations			(480,611	)		(452,467	)		(519,894	)
	Net loss		$	(32,741,274	)	$	(26,439,159	)	$	(28,491,153	)
	Weighted average shares outstanding used to compute basic and diluted net loss per share			61,612,957			43,422,001			28,824,417
	Basic and diluted net loss per share from continuing operations		$	(0.52	)	$	(0.60	)	$	(0.97	)
	Basic and diluted net loss per share from discontinued operations		$	(0.01	)	$	(0.01	)	$	(0.02	)
	Basic and diluted net loss per share		$	(0.53	)	$	(0.61	)	$	(0.99	)
	Outstanding options, warrants and restricted stock units were excluded from the computation of diluted net loss per share because the effect would have been anti-dilutive for all periods presented below:
			2014			2013			2012
	Outstanding options			302,729			428,258			447,359
	Restricted stock units			3,374,940			3,326,282			1,534,200
	Outstanding warrants			23,478,181			16,267,659			9,935,912
	Total			27,155,850			20,022,199			11,917,471
Comprehensive Income (Loss)	Comprehensive Income (Loss)
	Comprehensive income (loss) is comprised of net losses and other comprehensive income (or “OCI”). OCI includes certain changes in stockholders’ equity that are excluded from net losses. Specifically, we include in OCI changes in unrealized gains and losses on our marketable securities and unrealized gains and losses on foreign currency translations.
	The components of our accumulated OCI, as of December 31 of each year shown, are as follows:
			2014			2013
	Unrealized gain on foreign currency translation		$	65,390		$	252,101
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In August 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-15, “Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern,” to provide guidance on management’s responsibility in evaluating whether there is substantial doubt about a company’s ability to continue as a going concern and to provide related footnote disclosures. This update is effective for annual periods ending after December 15, 2016, and interim periods within annual periods beginning after December 15, 2016. Early application is permitted for annual or interim reporting periods for which the financial statements have not previously been issued. We do not expect the adoption of ASU 2014-15 to have a significant impact on our Consolidated Financial Statements or related disclosures.
	In April 2014, the FASB issued ASU No. 2014-08, “Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity”. The amendments in ASU 2014-08 change the criteria for reporting discontinued operations while enhancing disclosures in this area. Under this guidance, only disposals representing a strategic shift in operations should be presented as discontinued operations. Those strategic shifts should have a major effect on the organization’s operations and financial results. This guidance is effective prospectively for all disposals of components of an entity that occur with annual periods beginning on or after December 15, 2014, and interim periods therein. We do not expect the adoption of ASU 2014-15 to have a significant impact on our Consolidated Financial Statements or related disclosures.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Estimated Useful Lives of Assets	Property, plant and equipment, including those held under capital lease, are stated at cost. Depreciation is computed by use of the straight-line method over the estimated useful lives of the assets, or the lease term if shorter, as follows:
	Building and improvements		3 - 20 years
	Machinery and equipment		3 - 10 years
	Furniture and fixtures		3 - 10 years
Basic and Dilutive Net Loss per Share Computations	The following are the basic and dilutive net loss per share computations for the last three fiscal years:
		2014			2013			2012
	Net loss from continuing operations	$	(32,260,663	)	$	(25,986,692	)	$	(27,971,259	)
	Net loss from discontinued operations		(480,611	)		(452,467	)		(519,894	)
	Net loss	$	(32,741,274	)	$	(26,439,159	)	$	(28,491,153	)
	Weighted average shares outstanding used to compute basic and diluted net loss per share		61,612,957			43,422,001			28,824,417
	Basic and diluted net loss per share from continuing operations	$	(0.52	)	$	(0.60	)	$	(0.97	)
	Basic and diluted net loss per share from discontinued operations	$	(0.01	)	$	(0.01	)	$	(0.02	)
	Basic and diluted net loss per share	$	(0.53	)	$	(0.61	)	$	(0.99	)
Outstanding Options, Warrants and Restricted Stock Units	Outstanding options, warrants and restricted stock units were excluded from the computation of diluted net loss per share because the effect would have been anti-dilutive for all periods presented below:
		2014			2013			2012
	Outstanding options		302,729			428,258			447,359
	Restricted stock units		3,374,940			3,326,282			1,534,200
	Outstanding warrants		23,478,181			16,267,659			9,935,912
	Total		27,155,850			20,022,199			11,917,471
Summary of Components of Accumulated OCI	The components of our accumulated OCI, as of December 31 of each year shown, are as follows:
		2014			2013
	Unrealized gain on foreign currency translation	$	65,390		$	252,101

Financial_Instruments_Tables

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Cash and Cash Equivalents	The following table summarizes the fair value of our cash and cash equivalents:
		Amortized		Gross		Gross		Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	December 31, 2014
	Cash	$	1,398,928	$	—	$	—	$	1,398,928
	Cash equivalents (money market accounts)		23,588,675		—		—		23,588,675
	Total cash, cash equivalents, and marketable securities	$	24,987,603	$	—	$	—	$	24,987,603
	December 31, 2013
	Cash	$	1,355,281	$	—	$	—	$	1,355,281
	Cash equivalents (money market accounts)		29,230,143		—		—		29,230,143
	Total cash, cash equivalents, and marketable securities	$	30,585,424	$	—	$	—	$	30,585,424

Fair_Value_Measurement_Tables

Fair Value Measurement (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Financial Assets and Liabilities Measured at Fair Value	The following table presents our financial assets and liabilities measured at fair value as of December 31, 2014:
		Fair Value Measurement
		at Reporting Date Using
		Quoted Prices			Unobservable			As of
		in Active Markets for			Inputs			December 31,
		Identical Assets			(Level 3)			2014
		(Level 1)
	Financial assets
	Cash equivalents:
	Money market funds	$	421,418		$	—		$	421,418
	U.S. Treasury debt obligations		23,167,257			—			23,167,257
	Total financial assets	$	23,588,675		$	—		$	23,588,675
	Financial liabilities
	Loan payable net of discounts	$	—		$	15,020,417		$	15,020,417
	Warrant liabilities		—			1,684,551			1,684,551
	Total financial liabilities	$	—		$	16,704,968		$	16,704,968
Roll Forward for Financial Assets and Liabilities Measured at Fair Value Using Significant Other Observable Inputs (Level 2)	The following table presents a roll forward for financial assets and liabilities measured at fair value using significant other observable inputs (Level 2) for 2014.
		Level 2			Settled			Level 2
		Beginning			$			Ending
		Balance 12/31/13						Balance 12/31/14
		$						$
	Bond obligation		125,000			(125,000	)		—
Roll Forward for Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3)	The following table presents a roll forward for liabilities measured at fair value using significant unobservable inputs (Level 3) for 2014.
		Warrant
		Liabilities
	Balance at December 31, 2013	$	5,541,809
	Less fair value of warrants exercised		(1,434,807	)
	Add change in fair value of warrants		(2,422,451	)
	Balance at December 31, 2014	$	1,684,551
		Loan
		Payable
	Balance at December 31, 2013	$	12,909,244
	Add loan proceeds		5,775,543
	Less repayments of principal		(3,857,971	)
	Add accretion of discount		193,601
	Balance at December 31, 2014	$	15,020,417
	Current portion	$	4,686,388
	Non-current portion		10,334,029
	Balance at December 31, 2014	$	15,020,417

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Summary of Property, Plant and Equipment Balances	Property, plant and equipment balances at December 31 are summarized below:
		2014			2013
	Building and improvements	$	6,794,556		$	6,751,393
	Machinery and equipment		8,161,291			7,837,140
	Furniture and fixtures		639,909			602,599
			15,595,756			15,191,132
	Less accumulated depreciation and amortization		(10,408,798	)		(9,886,448	)
	Property, plant and equipment, net	$	5,186,958		$	5,304,684

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Purchase Price Allocated	At April 1, 2009, the purchase price was allocated as follows:
		Allocated			Estimated Life of
		Purchase			Intangible Assets
		Price			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 represents changes in goodwill in 2014:
	Balance as of December 31, 2013	$	2,139,294
	Net deferred tax liability related to indefinite lived IPR&D		(110,735	)
	Foreign currency translation		(118,497	)
	Impairment		(1,910,062	)
	Balance as of December 31, 2014	$	—
Components of Other Intangible Assets	The components of our other intangible assets at December 31, 2014 are summarized below:
	Other Intangible Asset Class	Cost			Accumulated			Proceeds			Foreign Currency		Write Off/			Net Carrying		Weighted-
					Amortization			from sale			Translation		Impairment			Amount		Average
																		Amortization
																		Period
	Related to SC Proven product line	$	1,620,000		$	(1,200,186	)	$	(400,000	)	$	167,038	$	(186,852	)	$	—		8.0 years
	In-process research and development		1,340,000			(270,687	)		—			115,748		(1,185,061	)		—		Indefinite
	Patents		1,243,612			(886,723	)		—			—		—			356,889		17.0 years
	Total other intangible assets	$	4,203,612		$	(2,357,596	)	$	(400,000	)	$	282,786	$	(1,371,913	)	$	356,889		11.9 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 as follows:
	For the year ending December 31:
	2015	$	83,265
	2016	$	75,496
	2017	$	54,923
	2018	$	27,978
	2019	$	27,978

Other_Assets_Tables

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Summary of Other Assets, Non-Current	Other assets, non-current at December 31 are summarized below:
		2014		2013
	Security deposit (buildings and equipment lease)	$	373,717	$	413,717

Accounts_Payable_Tables

Accounts Payable (Tables)	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Summary of Accounts Payable	Accounts payable at December 31 are summarized below:
		2014		2013
	External services	$	1,352,710	$	863,030
	Supplies		339,762		263,866
	Other		126,359		25,007
	Total accounts payable	$	1,818,831	$	1,151,903

Accrued_Expenses_and_Other_Cur1

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Summary of Accrued Expenses	Accrued expenses at December 31 are summarized below:
		2014		2013
	External services	$	2,152,770	$	1,191,048
	Employee compensation		2,415,826		2,655,242
	Other		301,114		221,626
	Total accrued expenses and other current liabilities	$	4,869,710	$	4,067,916

Other_LongTerm_Liabilities_Tab

Other Long-Term Liabilities (Tables)	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Schedule of Other Long-Term Liabilities
		2014		2013
	Accrued interest on loan payable	$	1,093,568	$	497,134
	Employee compensation		156,439		186,439
	Net deferred tax liability		—		117,815
	Total other long-term liabilities	$	1,250,007	$	801,388

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Expense	Our stock-based compensation expense for the last three fiscal years was as follows:
			2014			2013			2012
	Research and development expense		$	608,840		$	1,219,308		$	1,280,298
	General and administrative expense			1,426,058			1,389,362			1,597,836
	Total stock-based compensation expense and effect on net loss		$	2,034,898		$	2,608,670		$	2,878,134
Schedule of Fair Value Option Award, Assumptions	The weighted-average assumptions used for the last three fiscal years are as follows:
			2014			2013			2012
	Expected term (years)(1)			4.2			5.1			6.4
	Risk-free interest rate(2)			1.3	%		1.2	%		1.4	%
	Expected volatility(3)			78.7	%		89.3	%		78.4	%
	Expected dividend yield(4)			0	%		0	%		0	%
	-1	The expected term represents the period during which our stock-based awards are expected to be outstanding. We estimated this amount based on historical experience of similar awards, giving consideration to the contractual terms of the awards, vesting requirements, and expectation of future employee behavior, including post-vesting terminations.
	-2	The risk-free interest rate is based on U.S. Treasury debt securities with maturities close to the expected term of the option as of the date of grant.
	-3	Expected volatility is based on historical volatility over the most recent historical period equal to the length of the expected term of the option as of the date of grant.
	-4	We have neither declared nor paid dividends on any share of common stock and we do not expect to do so in the foreseeable future.
Stock Option Activity	A summary of our stock option activity and related information for the last three fiscal years is as follows:
			Outstanding Options
			Number of			Weighted-			Weighted-Average			Aggregate
			Shares			Average			Remaining			Intrinsic
						Exercise Price			Contractual Term			Value(1)
	Balance at December 31, 2011			875,498		$	20.13			5.5		$	—
	Granted			—			—
	Exercised			(3,629	)	$	1					$	4,319
	Cancelled (forfeited and expired)			(424,510	)	$	20.86
	Balance at December 31, 2012			447,359		$	19.59			5.1		$	2,175
	Granted			—
	Exercised			(3,452	)	$	1					$	2,214
	Cancelled (forfeited and expired)			(15,649	)	$	13.06
	Balance at December 31, 2013			428,258		$	19.97			4.3		$	—
	Granted			—
	Exercised			—			—						—
	Cancelled (forfeited and expired)			(125,529	)	$	24.3
	Balance at December 31, 2014			302,729		$	18.18			3.3		$	—
	Exercisable at December 31, 2014			302,729		$	18.18			3.3		$	—
	Vested and expected to vest(2)			302,729		$	18.18			3.3		$	—
	-1	Aggregate intrinsic value represents the value of the closing price per share of our common stock on the last trading day of the fiscal period in excess of the exercise price multiplied by the number of options outstanding or exercisable, except for the “Exercised” line, which uses the closing price on the date exercised.
	-2	Number of shares includes options vested and those expected to vest net of estimated forfeitures.
Summary of Changes in Unvested Options	The following is a summary of changes in unvested options:
	Unvested Options		Number of			Weighted
			Options			Average
						Grant Date Fair
						Value
	Unvested options at December 31, 2013			18,466		$	8.11
	Granted			—			—
	Vested			(16,666	)	$	8.3
	Cancelled			(1,800	)	$	6.39
	Unvested options at December 31, 2014			—			—
Weighted Average Exercise Price and Remaining Term Information about Significant Option Groups Outstanding	The following table presents weighted average exercise price and remaining term information about significant option groups outstanding at December 31, 2014:
	Options Outstanding at December 31, 2014
	Range of		Number			Weighted Average			Weighted Average			Aggregate Intrinsic
	Exercise Prices		Outstanding			Remaining			Exercise			Value at December 31,
						Term (Yrs.)			Price			2014
	Less than $10.00			300			5.5		$	8.9		$	—
	$10.00 - $19.99			170,170			4.4		$	11.85			—
	$20.00 - $29.99			107,959			2.1		$	23.24			—
	$30.00 - $39.99			17,800			1.1		$	36.7			—
	$40.00 - $49.99			4,500			0.7		$	47.89			—
	$50.00 - $59.99			2,000			0.7		$	53.85			—
				302,729			3.3		$	18.18		$	—
	Vested Options Outstanding at December 31, 2014
	Range of Exercise Prices		Number			Weighted Average
			Outstanding			Exercise Price
	Less than $10.00			300		$	8.9
	$10.00 - $19.99			170,170		$	11.85
	$20.00 - $29.99			107,959		$	23.24
	$30.00 - $39.99			17,800		$	36.7
	$40.00 - $49.99			4,500		$	47.89
	$50.00 - $59.99			2,000		$	53.85
				302,729		$	18.18
Summary of Restricted Stock Unit Activity	A summary of our restricted stock unit activity for the year ended December 31, 2014 is as follows:
			Number of			Weighted Average
			RSUs			Grant Date Fair
						Value
	Outstanding at January 1, 2014			3,326,282		$	1.68
	Granted(1)			1,674,874		$	1.5
	Vested and exercised			(851,216	)	$	1.71
	Cancelled			(775,000	)	$	1.8
	Outstanding at December 31, 2014			3,374,940		$	1.55
	-1	228,874 of these restricted stock units vest and convert into shares of our common stock after one year from the date of grant. 150,000 of these restricted stock units vest and convert into shares of our common stock over a three year period from the date of grant: one-third of the award will vest on each grant date anniversary following the grant. 1,296,000 of these restricted stock units 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.

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Summary of Components of Rent Expense	The table below summarizes the components of rent expense for the fiscal year ended December 31, as follows:
			2014		2013			2012
	Rent expense		$	1,955,747	$	2,612,899		$	2,932,104
	Sublease income			—		(53,726	)		(411,885	)
	Rent expense, net		$	1,955,747	$	2,559,173		$	2,520,219
Future Minimum Payments Under All Leases and Loan Payable	Future minimum payments under all leases and loan payable at December 31, 2014 are as follows:
			Loan1		Loan			Capital			Operating
			Payable CIRM		Payable SVB			Leases			Leases
	2015		$	679,166	$	4,322,035		$	21,591		$	1,981,461
	2016					1,440,678			9,454			1,968,459
	2017					—			—			2,014,706
	2018					—			—			2,061,260
	2019					—			—			2,108,130
	Thereafter					—			—			6,088,780
	Total minimum lease and loan payments			679,166		5,762,713			31,045		$	16,222,796
	Less amounts representing interest					240,899			1,624
	Principal amounts of bond payable, loan payable and capital lease obligations			679,166		5,521,814			29,421
	Less current maturities			679,166		4,099,319			20,191
	Bond payable, loan payable and capital lease obligations, less current maturities		$	—	$	1,422,495		$	9,230
	1	An aggregate of approximately $9.2 million of principal and accrued interest under the CIRM Loan Agreement is not included. In April 2013, we entered into an agreement with the CIRM under which CIRM will provide up to approximately $19.3 million as a forgivable loan, in accordance with mutually agreed upon terms and conditions and CIRM regulations. The CIRM loan was to help fund preclinical development of our HuCNS-SC cells for Alzheimer’s disease. Between July 2013 and August 2014, we received in aggregate, approximately $9.6 million as disbursements of the loan provided under the CIRM Loan Agreement. However in December 2014, as findings under this pre-clinical study in Alzheimer’s disease did not meet pre-determined criteria for ongoing funding for this program by CIRM, we decided to wind down this pre-clinical study which had been funded in part by the CIRM loan agreement. Under the terms of the CIRM loan agreement, principal amount of approximately $8,917,000 and accrued interest of approximately $243,000 were forgiven. However, authoritative accounting guidance requires certain conditions (which includes a legal release from the creditor) to be met before a liability can be extinguished and derecognized. In February 2015, we repaid CIRM approximately $679,000 of the aggregate loan proceeds received.

Warrant_Liability_Tables

Warrant Liability (Tables)	12 Months Ended
	Dec. 31, 2014
Text Block [Abstract]
Assumptions Used for Simulation Model	The assumptions used for the Monte Carlo simulation model to value the outstanding Series A Warrants at December 31, 2014 are as follows:
	Risk-free interest rate per year		0.7	%
	Expected volatility per year		53.4	%
	Expected dividend yield		0	%
	Expected life (years)		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 in 2014:
		Series A
		Number of			Fair value $
		Warrants
	Balance at December 31, 2013		8,116,895		$	5,541,809
	Less exercised		(1,180,015	)		(1,434,807	)
	Changes in fair value		—			(2,422,451	)
	Balance at December 31, 2014		6,936,880		$	1,684,551
Summary of Warrant Liability	The following table is a summary of our warrant liability as of December 31, 2014:
	Warrants	Number Outstanding			Exercise Price ($)			Fair value
					per share
	Warrants issued in 2009		400,000			15			—
	Series A Warrants		6,936,880			1.4			1,684,551
	Total		7,336,880					$	1,684,551

Loan_Payable_Tables

Loan Payable (Tables)	12 Months Ended
	Dec. 31, 2014
Summary of Changes in Carrying Value of Loan Payable	The following table is a summary of the changes in the carrying value of our loan payable in 2014:
		Silicon Valley			CIRM Loan		Total
		Bank Loan
	Loan payable at December 31, 2013	$	9,088,980		$	3,820,264	$	12,909,244
	Additional loan proceeds		—			5,775,543		5,775,543
	Repayment of principal		(3,857,971	)		—		(3,857,971	)
	Accretion of discount		193,601			—		193,601
	Carrying value of loan payable at 12/31/2014 (current and non-current)	$	5,424,610		$	9,595,807	$	15,020,417
	Carrying value of loan payable, current portion	$	4,007,222		$	679,166	$	4,686,388
	Carrying value of loan payable, non-current portion		1,417,388			8,916,641		10,334,029
	Total loan payable at December 31, 2014	$	5,424,610		$	9,595,807	$	15,020,417
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	%

Common_Stock_Tables

Common Stock (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Reserved Shares of Common Stock for Exercise of Options, Warrants and Other Contingent Issuances of Common Stock	We reserved the following shares of common stock for the exercise of options, warrants and other contingent issuances of common stock, as of December 31, 2014:
	Shares reserved for share based compensation	13,360,690
	Shares reserved for warrants related to financing transactions	23,078,181
	Total	36,438,871

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Loss before Income Tax Attributable to Geographic Location	Loss before income taxes is attributed to the following geographic locations for the years ended December 31,
		2014			2013
	United States	$	30,215,000		$	26,080,000
	Foreign		2,526,000			359,000
	Total loss before income taxes	$	32,741,000		$	26,439,000
Components of Deferred Tax Assets and Liabilities	Significant components of our deferred tax assets and liabilities at December 31 are as follows:
		2014			2013
	Deferred tax assets:
	Capitalized research and development costs	$	66,212,000		$	59,426,000
	Net operating losses		57,261,000			56,906,000
	Research and development credits		9,798,000			8,931,000
	Stock-based compensation		1,124,000			1,063,000
	Capital loss carryover		254,000			541,000
	Fixed assets		393,000			452,000
	Other		3,930,000			1,289,000
			138,972,000			128,608,000
	Valuation allowance		(138,972,000	)		(128,315,000	)
	Total deferred tax assets	$	—		$	293,000
	Deferred tax liability:
	Intangible assets		—			(293,000	)
	Total deferred tax liability	$	—		$	(293,000	)
	Net deferred tax assets	$	—		$	—
Reconciliation of Federal Income Tax Rate	The effective tax rate as a percentage of income before income taxes differs from the statutory federal income tax rate (when applied to income before income taxes) for the years ended December 31 as follows:
		2014			2013			2012
	Statutory federal income tax (benefit) rate		(34	)%		(34	)%		(34	)%
	State income tax (benefit) rate		—			—			(3.3	)
	Increase resulting from:
	Expenses not deductible for taxes		0.8			0.5			8.8
	Increase in valuation allowance		32.6			38.8			3.7
	Change in state deferred tax rate		0			1.1			17.7
	Change in foreign deferred tax rate		2.8			0.9			1.8
	Expiration of tax attributes		1.7			0.5			5.3
	Prior year true up		1.1			(0.7	)		—
	Tax credits		(2.4	)		(3.0	)		—
	Warrant valuation		(2.5	)		(4.1	)		—
	Effective tax (benefit) rate		0	%		0	%		0	%

Quarterly_Financial_Data_Table

Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Summary of Quarterly Financial Data
		2014 Quarter Ended
		December 31			September 30			June 30			March 31
		(In $ thousands, except per share amounts)
	Continuing operations:
	Total revenue		883			82			23			24
	Operating expenses		10,612			6,462			7,983			6,866
	Change in fair value of warrant liability		2,327			4,076			(3,654	)		(327	)
	Impairment of goodwill and other intangible assets		(2,440	)		—			—			—
	Interest and other expense, net		(266	)		(316	)		(357	)		(394	)
	Net loss from continuing operations		(10,108	)		(2,620	)		(11,971	)		(7,562	)
	Discontinued operations:
	Net loss from discontinued operations		(30	)		(137	)		(144	)		(58	)
	Net loss from disposal of assets		(111	)		—			—			—
	Basic and diluted net loss per share:
	Continuing operations	$	(0.15	)	$	(0.04	)	$	(0.21	)	$	(0.14	)
	Discontinued operations	$	(0.00	)	$	(0.00	)	$	(0.00	)	$	(0.00	)
	Basic and diluted net loss per share	$	(0.15	)	$	(0.04	)	$	(0.21	)	$	(0.14	)
		2013 Quarter Ended
		December 31			September 30			June 30			March 31
		(In thousands, except per share amounts)
	Continuing operations:
	Total revenue		45			38			33			56
	Operating expenses		9,341			6,628			6,131			6,165
	Change in fair value of warrant liability		2,828			(144	)		758			(189	)
	Interest and other income (expense), net		(380	)		(392	)		(405	)		30
	Net loss from continuing operations		(6,848	)		(7,126	)		(5,745	)		(6,268	)
	Discontinued operations:
	Net loss from discontinued operations		(115	)		(66	)		(124	)		(149	)
	Basic and diluted net loss per share:
	Continuing operations	$	(0.13	)	$	(0.17	)	$	(0.14	)	$	(0.16	)
	Discontinued operations	$	(0.00	)	$	(0.00	)	$	(0.01	)	$	(0.01	)
	Basic and diluted net loss per share	$	(0.13	)	$	(0.17	)	$	(0.15	)	$	(0.17	)

Summary_of_Significant_Account3

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

1 Months Ended

12 Months Ended

1 Months Ended

14 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

Jul. 31, 2014

Oct. 31, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Apr. 30, 2013

Aug. 31, 2014

Feb. 28, 2015

Dec. 31, 2014

Dec. 31, 2011

31-May-14

Nov. 30, 2008

Nov. 30, 2009

Apr. 01, 2009

Segment

Class of Warrant or Right [Line Items]

Number of segments

1

Accumulated deficit

($420,271,608)

($387,530,334)

($420,271,608)

Maturity period for money market and highly liquid investments

90 days

Aggregate purchase price

5,135,000

Percentage of purchase price allocated to goodwill

42.00%

Impairment of Goodwill

1,910,062

Other intangible assets, net

356,889

1,835,717

356,889

Impairment amount of intangible asset

530,000

530,000

655,000

Value of patent

0

Fair value of certain lab equipment

0

0

28,000

Proceeds from loan

5,775,543

Cash discount

100,000

100,000

Term of loan

3 years

Annual interest rate on loan

6.00%

6.00%

Final fee payment at the end of loan term

1,000,000

Exercise price of warrants

$2.17

$1.80

Initial carrying amount assigned to loan, net of discount

9,512,000

9,512,000

Fair value allocated to warrant

388,000

388,000

Note issuance costs

117,000

Deferred financing costs, discount and accretion percentage

9.00%

Common stock per unit

$1

Warrants issued per unit

$1

Number of shares issued upon Series B warrants exercise

11,299,435

12,845,500

CIRM [Member]

Class of Warrant or Right [Line Items]

Proceeds from loan

5,775,543

Approval of fund by California Institute for Regenerative Medicine (CIRM)

19,300,000

Aggregate proceeds from disbursement of the loan

9,600,000

Forgiveness of loan principal

8,917,000

Accrued interest forgiven

243,000

CIRM [Member] | Subsequent Events [Member]

Class of Warrant or Right [Line Items]

Repayment of aggregate loan proceeds received

679,000

Silicon Valley Bank [Member]

Class of Warrant or Right [Line Items]

Proceeds from loan

9,900,000

Cash discount

100,000

Common Stock [Member]

Class of Warrant or Right [Line Items]

Number of securities callable by warrants

1,180,015

1,180,015

Warrant component

0.85

0.5

Outstanding Warrants [Member]

Class of Warrant or Right [Line Items]

Fair value of warrant liability

1,685,000

1,685,000

Marketable debt securities, current [Member] | Minimum [Member]

Class of Warrant or Right [Line Items]

Investments with maturities

365 days or less

Marketable securities, non-current [Member] | Maximum [Member]

Class of Warrant or Right [Line Items]

Investments with maturities

Greater than 365 days

Stem Cell Sciences Holdings Ltd [Member]

Class of Warrant or Right [Line Items]

Aggregate purchase price

5,135,000

Percentage of purchase price allocated to goodwill

42.00%

Impairment of Goodwill

$1,910,000

Silicon Valley Bank Loan Agreement Warrant [Member]

Class of Warrant or Right [Line Items]

Term of warrant

10 years

Exercise price of warrants

$1.70

$1.70

Warrant expiration period

Apr-23

Silicon Valley Bank Loan Agreement Warrant [Member] | Common Stock [Member]

Class of Warrant or Right [Line Items]

Number of securities callable by warrants

293,531

293,531

December 2011 Financing [Member] | Common Stock [Member]

Class of Warrant or Right [Line Items]

Warrant component

1

1

Number of shares issued upon Series B warrants exercise

384,534

2,700,000

December 2011 Financing [Member] | Series A Warrants [Member]

Class of Warrant or Right [Line Items]

Term of warrant

5 years

Number of securities callable by warrants

8,000,000

Warrant component

1

1

Number of warrants issued upon Series B warrants exercise

2,700,000

December 2011 Financing [Member] | Series A Warrants [Member] | Common Stock [Member]

Class of Warrant or Right [Line Items]

Exercise price of warrants

1.4

December 2011 Financing [Member] | Series B Warrants [Member]

Class of Warrant or Right [Line Items]

Term of warrant

90 days

Number of securities callable by warrants

8,000,000

Exercise price of warrants

1.25

Number of warrants exercised

2,700,000

Number of warrants expired

5,300,000

November 2008 Financing [Member]

Class of Warrant or Right [Line Items]

Warrants issued

1,034,483

November 2008 Financing [Member] | Common Stock [Member]

Class of Warrant or Right [Line Items]

Number of securities callable by warrants

1,034,483

Exercise price of warrants

23

Warrant component

0.75

November 2008 Financing [Member] | Outstanding Warrants [Member]

Class of Warrant or Right [Line Items]

Term of warrant

5 years

November 2009 Financing [Member]

Class of Warrant or Right [Line Items]

Exercise price of warrants

$15

$15

November 2009 Financing [Member] | Common Stock [Member]

Class of Warrant or Right [Line Items]

Number of securities callable by warrants

400,000

Exercise price of warrants

15

Warrant component

0.4

November 2009 Financing [Member] | Outstanding Warrants [Member]

Class of Warrant or Right [Line Items]

Term of warrant

5 years

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Estimated Useful Lives of Assets (Detail)	12 Months Ended
	Dec. 31, 2014
Minimum [Member] | Building and improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Minimum [Member] | Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Minimum [Member] | Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Maximum [Member] | Building and improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	20 years
Maximum [Member] | Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Maximum [Member] | Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years

Summary_of_Significant_Account5

Summary of Significant Accounting Policies - Basic and Dilutive Net Loss per Share Computations (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Abstract]
Net loss from continuing operations	($10,108,000)	($2,620,000)	($11,971,000)	($7,562,000)	($6,848,000)	($7,126,000)	($5,745,000)	($6,268,000)	($32,260,663)	($25,986,692)	($27,971,259)
Net loss from discontinued operations									-480,611	-452,467	-519,894
Net loss									($32,741,274)	($26,439,159)	($28,491,153)
Weighted average shares outstanding used to compute basic and diluted net loss per share									61,612,957	43,422,001	28,824,417
Basic and diluted net loss per share from continuing operations	($0.15)	($0.04)	($0.21)	($0.14)	($0.13)	($0.17)	($0.14)	($0.16)	($0.52)	($0.60)	($0.97)
Basic and diluted net loss per share from discontinued operations	$0	$0	$0	$0	$0	$0	($0.01)	($0.01)	($0.01)	($0.01)	($0.02)
Basic and diluted net loss per share	($0.15)	($0.04)	($0.21)	($0.14)	($0.13)	($0.17)	($0.15)	($0.17)	($0.53)	($0.61)	($0.99)

Summary_of_Significant_Account6

Summary of Significant Accounting Policies - Outstanding Options, Warrants and Restricted Stock Units (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Class of Stock [Line Items]
Outstanding options, warrants and restricted stock units	27,155,850	20,022,199	11,917,471
Options [Member]
Class of Stock [Line Items]
Outstanding options, warrants and restricted stock units	302,729	428,258	447,359
Restricted stock units [Member]
Class of Stock [Line Items]
Outstanding options, warrants and restricted stock units	3,374,940	3,326,282	1,534,200
Outstanding Warrants [Member]
Class of Stock [Line Items]
Outstanding options, warrants and restricted stock units	23,478,181	16,267,659	9,935,912

Summary_of_Significant_Account7

Summary of Significant Accounting Policies - Summary of Components of Accumulated OCI (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized gain on foreign currency translation	$65,390	$252,101

Financial_Instruments_Cash_and

Financial Instruments - Cash and Cash Equivalents (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$24,987,603	$30,585,424
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	24,987,603	30,585,424
Cash [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,398,928	1,355,281
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	1,398,928	1,355,281
Cash equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	23,588,675	29,230,143
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$23,588,675	$29,230,143

Financial_Instruments_Addition

Financial Instruments - Additional Information (Detail) (Subsidiaries [Member], USD $)	Dec. 31, 2014
Subsidiaries [Member]
Cash and Cash Equivalents [Line Items]
Cash	$652,000

Fair_Value_Measurement_Financi

Fair Value Measurement - Financial Assets and Liabilities Measured at Fair Value (Detail) (USD $)	Dec. 31, 2014
Outstanding Warrants [Member]
Financial liabilities:
Total financial liabilities	$1,684,551
Fair Value, Measurements [Member]
Financial assets:
Total financial assets	23,588,675
Financial liabilities:
Total financial liabilities	16,704,968
Fair Value, Measurements [Member] | Money market funds [Member] | Cash equivalents [Member]
Financial assets:
Total financial assets	421,418
Fair Value, Measurements [Member] | U.S. Treasury debt obligations [Member] | Cash equivalents [Member]
Financial assets:
Total financial assets	23,167,257
Fair Value, Measurements [Member] | Loan Payable [Member]
Financial liabilities:
Total financial liabilities	15,020,417
Fair Value, Measurements [Member] | Outstanding Warrants [Member]
Financial liabilities:
Total financial liabilities	1,684,551
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements [Member]
Financial assets:
Total financial assets	23,588,675
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	421,418
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	23,167,257
Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member]
Financial liabilities:
Total financial liabilities	16,704,968
Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member] | Loan Payable [Member]
Financial liabilities:
Total financial liabilities	15,020,417
Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member] | Outstanding Warrants [Member]
Financial liabilities:
Total financial liabilities	$1,684,551

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 $)	12 Months Ended
	Dec. 31, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable debt securities, Ending Balance	$23,588,675
Significant Other Observable Inputs (Level 2) [Member] | Bond obligation [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Marketable debt securities, Beginning Balance	125,000
Financial liabilities change settled in earning fair value disclosure	($125,000)

Fair_Value_Measurement_Roll_Fo1

Fair Value Measurement - Roll Forward for Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3) (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Add loan proceeds									$5,775,543
Less repayments of principal	-3,857,971								-3,857,971
Add change in fair value of warrants	2,327,000	4,076,000	-3,654,000	-327,000	2,828,000	-144,000	758,000	-189,000	-2,422,451	-3,253,253	5,944,571
Outstanding Warrants [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2013				5,541,809					5,541,809
Less fair value of warrants exercised									-1,434,807
Add change in fair value of warrants									-2,422,451
Balance at December 31, 2014	1,684,551								1,684,551
Balance at December 31, 2014	1,684,551								1,684,551
Loan Payable [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at December 31, 2013				12,909,244					12,909,244
Add loan proceeds									5,775,543
Less repayments of principal	-3,857,971								-3,857,971
Add accretion of discount									193,601
Balance at December 31, 2014	15,020,417								15,020,417
Current portion	4,686,388								4,686,388
Non-current portion	10,334,029								10,334,029
Balance at December 31, 2014	$15,020,417								$15,020,417

Property_Plant_and_Equipment_S

Property, Plant and Equipment - Summary of Property, Plant and Equipment Balances (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross, Total	$15,595,756	$15,191,132
Less accumulated depreciation and amortization	-10,408,798	-9,886,448
Property, plant and equipment, net	5,186,958	5,304,684
Building and improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross, Total	6,794,556	6,751,393
Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross, Total	8,161,291	7,837,140
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross, Total	$639,909	$602,599

Property_Plant_and_Equipment_A

Property, Plant and Equipment - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense	$1,008,000	$789,000	$728,000

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Apr. 30, 2009	Apr. 01, 2009	Dec. 31, 2011
Acquired Finite-Lived Intangible Assets [Line Items]
Aggregate purchase price						5,135,000
Impairment amount of intangible asset	530,000	530,000					655,000
Useful life		11 years 10 months 24 days
Proceeds from sale of indefinite intangible assets	400,000	400,000
Percentage of purchase price allocated to goodwill		42.00%
Impairment of Goodwill		1,910,062
Amortization expense		$299,000	$269,000	$264,000
In-process research and development [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Minimum expiration year of intangible assets		2027
Trade name [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Useful life		15 years			15 years	15 years

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets - Purchase Price Allocated (Detail) (USD $)	0 Months Ended		12 Months Ended
	Apr. 30, 2009	Apr. 01, 2009	Dec. 31, 2014	Apr. 01, 2009
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period			11 years 10 months 24 days
Net tangible assets		$36,000		$36,000
Total		5,135,000		5,135,000
Customer relationships and developed technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Allocated purchase Price		1,310,000		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		1,340,000
Trade name [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted-Average Amortization Period	15 years	15 years	15 years
Allocated purchase Price		310,000		310,000
Goodwill [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill		$2,139,000		$2,139,000

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets - Changes in Goodwill (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Balance as of December 31, 2013	$2,139,294
Net deferred tax liability		-293,000
Foreign currency translation	-118,497
Impairment	-1,910,062
In-process research and development [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Net deferred tax liability	($110,735)

Goodwill_and_Other_Intangible_5

Goodwill and Other Intangible Assets - Components of Other Intangible Assets (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	$4,203,612	$4,203,612
Accumulated Amortization	-2,357,596	-2,357,596
Proceeds from sale	-400,000	-400,000
Foreign Currency Translation		282,786
Write Off/Impairment	-1,371,913	-1,371,913
Net Carrying Amount	356,889	356,889	1,835,717
Weighted-Average Amortization Period		11 years 10 months 24 days
Related to SC Proven product line [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	1,620,000	1,620,000
Accumulated Amortization	-1,200,186	-1,200,186
Proceeds from sale		-400,000
Foreign Currency Translation		167,038
Write Off/Impairment	-186,852	-186,852
Weighted-Average Amortization Period		8 years
In-process research and development [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	1,340,000	1,340,000
Accumulated Amortization	-270,687	-270,687
Foreign Currency Translation		115,748
Write Off/Impairment	-1,185,061	-1,185,061
Patents [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Cost	1,243,612	1,243,612
Accumulated Amortization	-886,723	-886,723
Net Carrying Amount	$356,889	$356,889
Weighted-Average Amortization Period		17 years

Goodwill_and_Other_Intangible_6

Goodwill and Other Intangible Assets - Expected Future Annual Amortization Expense (Detail) (USD $)	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
2015	$83,265
2016	75,496
2017	54,923
2018	27,978
2019	$27,978

Other_Assets_Summary_of_Other_

Other Assets - Summary of Other Assets, Non-Current (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Summary Other assets
Security deposit (buildings and equipment lease)	$373,717	$413,717

Accounts_Payable_Summary_of_Ac

Accounts Payable - Summary of Accounts Payable (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Accounts Payable [Abstract]
External services	$1,352,710	$863,030
Supplies	339,762	263,866
Other	126,359	25,007
Total accounts payable	$1,818,831	$1,151,903

Accrued_Expenses_and_Other_Cur2

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Payables and Accruals [Abstract]
External services	$2,152,770	$1,191,048
Employee compensation	2,415,826	2,655,242
Other	301,114	221,626
Total accrued expenses and other current liabilities	$4,869,710	$4,067,916

Other_LongTerm_Liabilities_Sch

Other Long-Term Liabilities - Schedule of Other Long-Term Liabilities (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Other Long Term Liabilities [Abstract]
Accrued interest on loan payable	$1,093,568	$497,134
Employee compensation	156,439	186,439
Net deferred tax liability		117,815
Total other long-term liabilities	$1,250,007	$801,388

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 20, 2013
	Incentive_Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity incentive plans	3
Shares authorized	225,000,000	225,000,000
Term of years	4 years 2 months 12 days	5 years 1 month 6 days	6 years 4 months 24 days
Total unrecognized compensation expense	$3,262,000
Vesting period	2 years 9 months 18 days
Options granted	0	0	0
Intrinsic value of options at time of exercise		2,214	4,319
Options exercised	0	3,452	3,629
Exercise price	$18.18
Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized	9,683,022
Annual increase in number of shares of common stock	4.00%
Aggregate limit of shares issuable to incentive stock option awards	3,000,000
Initial grant of stock-based compensation in shares				6,000,000
Increase in percentage of outstanding number of shares of common stock				4.00%
Stock Appreciation Rights (SARs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of vested grant yearly	25.00%
Percentage of vested grant monthly	75.00%
Term of years	10 years
Vesting period of grant date	3 years
Exercise price	$20
Number of SARs, Granted	0
Number of SARs, Exercised	0
Number of SARs, Forfeited and expired	0
Reduced compensation expense	0	0	0
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units vest and convert into shares of our common stock	1 year
Restricted Stock [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
Restricted Stock [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of grant date	1 year
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]
Percentage of vested grant yearly	25.00%
Percentage of vested grant monthly	75.00%
Term of years	4 years
Unexercised vested option forfeiture	3 months
Estimated fair value	$138,000	$406,000	$627,000
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 $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense and effect on net loss	$2,034,898	$2,608,670	$2,878,134
Research and development expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense and effect on net loss	608,840	1,219,308	1,280,298
Selling, general and administrative expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense and effect on net loss	$1,426,058	$1,389,362	$1,597,836

StockBased_Compensation_Schedu

Stock-Based Compensation - Schedule of Fair Value Option Award, Assumptions (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected term (years)(1)	4 years 2 months 12 days	5 years 1 month 6 days	6 years 4 months 24 days
Risk-free interest rate(2)	1.30%	1.20%	1.40%
Expected volatility(3)	78.70%	89.30%	78.40%
Expected dividend yield(4)	0.00%	0.00%	0.00%

StockBased_Compensation_Stock_

Stock-Based Compensation - Stock Option Activity (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of Shares, Beginning balance	428,258	447,359	875,498
Number of Shares, Granted	0	0	0
Number of Shares, Exercised	0	-3,452	-3,629
Number of Shares, Cancelled (forfeited and expired)	-125,529	-15,649	-424,510
Number of Shares, Ending balance	302,729	428,258	447,359	875,498
Weighted-Average Exercise Price, Beginning balance	$19.97	$19.59	$20.13
Number of Shares, Exercisable	302,729
Weighted-Average Exercise Price, Granted	$0	$0	$0
Number of Shares, Vested and expected to vest	302,729
Weighted-Average Exercise Price, Exercised		$1	$1
Weighted-Average Exercise Price, Cancelled (forfeited and expired)	$24.30	$13.06	$20.86
Weighted-Average Exercise Price, Ending balance	$18.18	$19.97	$19.59	$20.13
Aggregate Intrinsic Value, Beginning balance		$2,175
Weighted-Average Exercise Price, Exercisable	$18.18
Aggregate Intrinsic Value, Exercised		2,214	4,319
Weighted-Average Exercise Price, Vested and expected to vest	$18.18
Aggregate Intrinsic Value, Ending balance			2,175
Weighted-Average Remaining Contractual Term, Outstanding	3 years 3 months 18 days	4 years 3 months 18 days	5 years 1 month 6 days	5 years 6 months
Aggregate Intrinsic Value, Exercisable	0
Weighted-Average Remaining Contractual Term, Exercisable	3 years 3 months 18 days
Aggregate Intrinsic Value, Vested and expected to vest	$0
Weighted-Average Remaining Contractual Term, Vested and expected to vest	3 years 3 months 18 days

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Changes in Unvested Options (Detail) (Unvested stock options [Member], USD $)	12 Months Ended
	Dec. 31, 2014
Unvested stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options, Beginning balance	18,466
Number of Options, Granted	0
Number of Options, Vested	-16,666
Number of Options, Cancelled	-1,800
Weighted-Average Grant Date Fair Value, Beginning balance	$8.11
Weighted-Average Grant Date Fair Value, Granted	$0
Weighted-Average Grant Date Fair Value, Vested	$8.30
Weighted-Average Grant Date Fair Value, Cancelled	$6.39

StockBased_Compensation_Weight

Stock-Based Compensation - Weighted Average Exercise Price and Remaining Term Information about Significant Option Groups Outstanding (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding	302,729
Weighted Average Remaining Term	3 years 3 months 18 days
Weighted Average Exercise Price	$18.18
Aggregate Intrinsic Value	$0
Vested Options [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding	302,729
Weighted Average Exercise Price	$18.18
Less than $10.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Upper Range	$10
Number Outstanding	300
Weighted Average Remaining Term	5 years 6 months
Weighted Average Exercise Price	$8.90
Aggregate Intrinsic Value	0
Less than $10.00 [Member] | Vested Options [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding	300
Weighted Average Exercise Price	$8.90
$10.00 - $19.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range	$10
Exercise Price Upper Range	$19.99
Number Outstanding	170,170
Weighted Average Remaining Term	4 years 4 months 24 days
Weighted Average Exercise Price	$11.85
Aggregate Intrinsic Value	0
$10.00 - $19.99 [Member] | Vested Options [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding	170,170
Weighted Average Exercise Price	$11.85
$20.00 - $29.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range	$20
Exercise Price Upper Range	$29.99
Number Outstanding	107,959
Weighted Average Remaining Term	2 years 1 month 6 days
Weighted Average Exercise Price	$23.24
Aggregate Intrinsic Value	0
$20.00 - $29.99 [Member] | Vested Options [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding	107,959
Weighted Average Exercise Price	$23.24
$30.00 - $39.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range	$30
Exercise Price Upper Range	$39.99
Number Outstanding	17,800
Weighted Average Remaining Term	1 year 1 month 6 days
Weighted Average Exercise Price	$36.70
Aggregate Intrinsic Value	0
$30.00 - $39.99 [Member] | Vested Options [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding	17,800
Weighted Average Exercise Price	$36.70
$40.00 - $49.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range	$40
Exercise Price Upper Range	$49.99
Number Outstanding	4,500
Weighted Average Remaining Term	8 months 12 days
Weighted Average Exercise Price	$47.89
Aggregate Intrinsic Value	0
$40.00 - $49.99 [Member] | Vested Options [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding	4,500
Weighted Average Exercise Price	$47.89
$50.00 - $59.99 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price Lower Range	$50
Exercise Price Upper Range	$59.99
Number Outstanding	2,000
Weighted Average Remaining Term	8 months 12 days
Weighted Average Exercise Price	$53.85
Aggregate Intrinsic Value	$0
$50.00 - $59.99 [Member] | Vested Options [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding	2,000
Weighted Average Exercise Price	$53.85

StockBased_Compensation_Summar1

Stock-Based Compensation - Summary of Restricted Stock Unit Activity (Detail) (Restricted stock units [Member], USD $)	12 Months Ended
	Dec. 31, 2014
Restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSUs, Beginning balance	3,326,282
Number of RSUs, Granted	1,674,874
Number of RSUs, Vested	-851,216
Number of RSUs, Cancelled	-775,000
Number of RSUs, Ending balance	3,374,940
Weighted Average Grant Date Fair Value, Beginning balance	$1.68
Weighted Average Grant Date Fair Value, Granted	$1.50
Weighted Average Grant Date Fair Value, Vested	$1.71
Weighted Average Grant Date Fair Value, Cancelled	$1.80
Weighted Average Grant Date Fair Value, Ending balance	$1.55

StockBased_Compensation_Summar2

Stock-Based Compensation - Summary of Restricted Stock Unit Activity (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units vest description	228,874 of these restricted stock units vest and convert into shares of our common stock after one year from the date of grant. 150,000 of these restricted stock units vest and convert into shares of our common stock over a three year period from the date of grant: one-third of the award will vest on each grant date anniversary following the grant. 1,296,000 of these restricted stock units 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.
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted units would vest over vesting period	228,874
Restricted stock units vest and convert into shares of our common stock	1 year
Restricted Stock Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted units would vest over vesting period	150,000
Restricted stock units vest and convert into shares of our common stock	3 years
Restricted stock units vested description after specified period	0.3333
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
Restricted stock units vested description after specified period	0.25
Number of restricted units vest and convert into common stock over next fiscal year	1,296,000

WindDown_and_Exit_Costs_Additi

Wind-Down and Exit Costs - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Wind Down Expenses [Abstract]
Amount of wind-down reserve			$854,000
Payments net of subtenant income recorded against reserve		916,000
Additional expense recorded to revise estimated reserve at period-end		$62,000
Lease termination date	30-Jun-13

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail)

1 Months Ended

12 Months Ended

1 Months Ended

1 Months Ended

1 Months Ended

12 Months Ended

Jul. 31, 2006

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2014

Dec. 31, 2014

Dec. 31, 2010

Dec. 31, 2014

Dec. 31, 2013

Mar. 31, 2013

Dec. 31, 2014

Dec. 31, 2013

Oct. 31, 2013

Dec. 31, 2014

Claim

USD ($)

USD ($)

Pilot Manufacturing Facility [Member]

Cell Processing Facility [Member]

BMR-Gateway Boulevard LLC [Member]

BMR-Gateway Boulevard LLC [Member]

BMR-Gateway Boulevard LLC [Member]

Prologis, L.P [Member]

Prologis, L.P [Member]

Prologis, L.P [Member]

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

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

sqft

sqft

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

GBP (£)

Commitment And Contingencies [Line Items]

Proceeds from the issuance of industrial revenue bonds

$5,000,000

Period of maturity

2014-08

Facility square-feet

21,000

3,000

Term of lease

11 years 6 months

10 years

3 years

Rent over term of lease

17,869,000

3,497,000

Deferred rent under sublease agreement

85,925

34,366

1,429,000

1,434,000

391,000

391,000

Rental payments under the existing lease

£ 53,000

Lease termination date

30-Jun-13

31-Oct-14

Number of patients violate claims of Neuralstem's activities

4

Commitments_and_Contingencies_2

Commitments and Contingencies - Summary of Components of Rent Expense (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Leases [Abstract]
Rent expense	$1,955,747	$2,612,899	$2,932,104
Sublease income		-53,726	-411,885
Rent expense, net	$1,955,747	$2,559,173	$2,520,219

Commitments_and_Contingencies_3

Commitments and Contingencies - Future Minimum Payments Under All Leases and Loan Payable (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Loss Contingencies [Line Items]
Less current maturities, bond payable and loan payable		$125,000
Less current maturities, Capital Leases	20,191	21,316
CIRM [Member]
Loss Contingencies [Line Items]
2015	679,166
2017	0
2018	0
2019	0
Thereafter	0
Total minimum loan payments	679,166
Less amounts representing interest	0
Principal amounts of bond payable and loan payable	679,166
Principal amounts of bond payable and loan payable	679,166
Less current maturities, bond payable and loan payable	679,166
Silicon Valley Bank [Member]
Loss Contingencies [Line Items]
2015	4,322,035
2016	1,440,678
2017	0
2018	0
2019	0
Thereafter	0
Total minimum loan payments	5,762,713
Less amounts representing interest	240,899
Principal amounts of bond payable and loan payable	5,521,814
Principal amounts of bond payable and loan payable	5,521,814
Less current maturities, bond payable and loan payable	4,099,319
Bond payable and loan payable, less current maturities	1,422,495
Operating Leases [Member]
Loss Contingencies [Line Items]
Operating Leases, 2015	1,981,461
Operating Leases, 2016	1,968,459
Operating Leases, 2017	2,014,706
Operating Leases, 2018	2,061,260
Operating Leases, 2019	2,108,130
Operating Leases, Thereafter	6,088,780
Total minimum lease payments, Operating Leases	16,222,796
Capital Leases [Member]
Loss Contingencies [Line Items]
Capital Leases, 2015	21,591
Capital Leases, 2016	9,454
Capital Leases, 2017	0
Capital Leases, 2018	0
Capital Leases, 2019	0
Capital Leases, Thereafter	0
Total minimum lease payments, Capital Leases	31,045
Less amounts representing interest, Capital Leases	1,624
Principal amounts of bond payable, loan payable and capital lease obligations, Capital Leases	29,421
Principal amounts of bond payable, loan payable and capital lease obligations, Capital Leases	29,421
Less current maturities, Capital Leases	20,191
Capital Leases, Less current maturities	$9,230

Commitments_and_Contingencies_4

Commitments and Contingencies - Future Minimum Payments Under All Leases and Loan Payable (Parenthetical) (Detail) (USD $)	12 Months Ended	1 Months Ended	14 Months Ended	1 Months Ended
	Dec. 31, 2014	Apr. 30, 2013	Aug. 31, 2014	Feb. 28, 2015
Loss Contingencies [Line Items]
Proceeds from principal and accrued interest	$9,200,000
CIRM [Member]
Loss Contingencies [Line Items]
Approval of fund by California Institute for Regenerative Medicine (CIRM)		19,300,000
Aggregate proceeds from disbursement of the loan			9,600,000
Forgiveness of loan principal	8,917,000
Accrued interest forgiven	243,000
Subsequent Events [Member] | CIRM [Member]
Loss Contingencies [Line Items]
Repayment of aggregate loan proceeds received				$679,000

Warrant_Liability_Additional_I

Warrant Liability - Additional Information (Detail) (USD $)	1 Months Ended			12 Months Ended			6 Months Ended	1 Months Ended	12 Months Ended
	Jul. 31, 2014	Oct. 31, 2013	Nov. 30, 2008	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Nov. 30, 2009	Dec. 31, 2011
Class of Warrant or Right [Line Items]
Exercise price of warrants	$2.17	$1.80
Warrants expired unexercised			2014-05
Number of shares issued upon warrants exercise	11,299,435	12,845,500
Outstanding Warrants [Member]
Class of Warrant or Right [Line Items]
Number of shares of common stock in each unit sold to institutional investors	1	1	1
Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Exercise price of warrants				$1.40
Proceeds from sale of stock				$1,652,000	$538,000	$3,078,000
Common Stock [Member]
Class of Warrant or Right [Line Items]
Number of securities callable by each warrant or right warrants	0.85	0.5
Number of shares of common stock in each unit sold to institutional investors	1	1
Number of securities callable by warrants				1,180,015
Number of shares issued upon warrants exercise						2,198,571	2,700,000
November 2008 Financing [Member]
Class of Warrant or Right [Line Items]
Number of units sold to investors			1,379,310
Price per unit			14.5
Gross proceeds from units sold to investors			20,000,000
Proceeds from sale of stock			18,637,000
November 2008 Financing [Member] | Common Stock [Member]
Class of Warrant or Right [Line Items]
Number of securities callable by each warrant or right warrants			0.75
Exercise price of warrants			23
Number of securities callable by warrants			1,034,483
November 2009 Financing [Member]
Class of Warrant or Right [Line Items]
Price per unit								$12.50
Gross proceeds from units sold to investors								12,500,000
Exercise price of warrants				$15
Proceeds from sale of stock								$11,985,000
Number of units sold to investors								1,000,000
November 2009 Financing [Member] | Common Stock [Member]
Class of Warrant or Right [Line Items]
Number of securities callable by each warrant or right warrants								0.4
Exercise price of warrants								$15
Number of securities callable by warrants								400,000
Number of warrants in each unit sold to institutional investors								1
December 2011 Financing [Member]
Class of Warrant or Right [Line Items]
Price per unit									$1.25
Number of units sold to investors									10,000,000
Number of Series A warrants in each unit issued in public offering									1
December 2011 Financing [Member] | Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Number of securities callable by warrants									8,000,000
Warrant expiration				Dec-16
Number of warrants exercised				1,180,015	384,534	2,198,571
Number of shares issued upon warrants exercise						2,700,000
December 2011 Financing [Member] | Series B Warrant [Member]
Class of Warrant or Right [Line Items]
Number of securities callable by warrants									8,000,000
Term of warrant									90 days
Warrant expiration				2012-May-02
Number of warrants exercised						2,700,000
Number of warrants expired				5,300,000
December 2011 Financing [Member] | Common Stock [Member]
Class of Warrant or Right [Line Items]
Number of securities callable by each warrant or right warrants				1
Number of shares issued upon warrants exercise					384,534	2,700,000
Number of shares issued upon warrants exercise				1,180,015	384,534	2,198,571
December 2011 Financing [Member] | Common Stock [Member] | Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Exercise price of warrants									$1.40
December 2011 Financing [Member] | Capital Units [Member] | Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Number of securities callable by each warrant or right warrants									1
December 2011 Financing [Member] | Capital Units [Member] | Series B Warrant [Member]
Class of Warrant or Right [Line Items]
Number of securities callable by each warrant or right warrants									1

Warrant_Liability_Assumptions_

Warrant Liability - Assumptions Used for Monte Carlo Simulation Model (Detail) (Series A Warrants [Member])	12 Months Ended
	Dec. 31, 2014
Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Risk-free interest rate per year	0.70%
Expected volatility per year	53.40%
Expected dividend yield	0.00%
Expected life (years)	2 years

Warrant_Liability_Summary_of_C

Warrant Liability - Summary of Changes in Fair Value of Warrant Liability (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014
Class of Warrant or Right [Line Items]
Number of Warrants, ending balance	7,336,880
Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Number of Warrants, beginning balance	8,116,895
Number of Warrants, Less exercised	-1,180,015
Number of Warrants, changes in fair value	0
Number of Warrants, ending balance	6,936,880
Fair value of warrant liability, beginning balance	$5,541,809
Fair value of warrants exercised	-1,434,807
Fair value, changes in fair value at period end	-2,422,451
Fair value of warrant liability, ending balance	$1,684,551

Warrant_Liability_Summary_of_W

Warrant Liability - Summary of Warrant Liability (Detail) (USD $)	Dec. 31, 2014	Jul. 31, 2014	Oct. 31, 2013
Class of Warrant or Right [Line Items]
Number Outstanding	7,336,880
Exercise Price per share		$2.17	$1.80
Outstanding Warrants [Member]
Class of Warrant or Right [Line Items]
Fair Value	1,684,551
Series A Warrants [Member]
Class of Warrant or Right [Line Items]
Number Outstanding	6,936,880
Exercise Price per share	1.4
Series A Warrants [Member] | Outstanding Warrants [Member]
Class of Warrant or Right [Line Items]
Fair Value	1,684,551
November 2009 Financing [Member]
Class of Warrant or Right [Line Items]
Number Outstanding	400,000
Exercise Price per share	15

Loan_Payable_Additional_Inform

Loan Payable - Additional Information (Detail) (USD $)	12 Months Ended	1 Months Ended	14 Months Ended	1 Months Ended
	Dec. 31, 2014	Apr. 30, 2013	Aug. 31, 2014	Feb. 28, 2015	Jul. 31, 2014	Oct. 31, 2013
Debt Instrument [Line Items]
Proceeds from loan	$5,775,543
Loan term	3 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
Exercise price of warrant					$2.17	$1.80
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%
Common Stock [Member]
Debt Instrument [Line Items]
Number of shares of common stock acquired using warrant	1,180,015
CIRM [Member]
Debt Instrument [Line Items]
Proceeds from loan	5,775,543
Approval of fund by California Institute for Regenerative Medicine (CIRM)		19,300,000
Aggregate proceeds from disbursement of the loan			9,600,000
Forgiveness of loan principal	8,917,000
Accrued interest forgiven	243,000
Subsequent Events [Member] | CIRM [Member]
Debt Instrument [Line Items]
Repayment of aggregate loan proceeds received				679,000
Silicon Valley Bank Loan Agreement Warrant [Member]
Debt Instrument [Line Items]
Term of warrant expiration	10 years
Exercise price of warrant	$1.70
Warrant expiration period	Apr-23
Silicon Valley Bank Loan Agreement Warrant [Member] | Common Stock [Member]
Debt Instrument [Line Items]
Number of shares of common stock acquired using warrant	293,531
Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Proceeds from loan		9,900,000
Cash discount		$100,000

Loan_Payable_Assumptions_Used_

Loan Payable - Assumptions Used for Black-Scholes Option Pricing Model (Detail) (Silicon Valley Bank Loan Agreement Warrant [Member])	12 Months Ended
	Dec. 31, 2014
Silicon Valley Bank Loan Agreement Warrant [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Expected life (years)	10 years
Risk-free interest rate	1.90%
Expected volatility	88.10%
Expected dividend yield	0.00%

Loan_Payable_Summary_of_Change

Loan Payable - Summary of Changes in Carrying Value of Loan Payable (Detail) (USD $)	12 Months Ended	1 Months Ended
	Dec. 31, 2014	Apr. 30, 2013	Dec. 31, 2013
Debt Instrument [Line Items]
Carrying value of loan payable (current and non-current) Beginning Balance	$12,909,244
Additional loan proceeds	5,775,543
Repayment of principal	-3,857,971
Accretion of discount	193,601
Carrying value of loan payable (current and non-current) Ending Balance	15,020,417
Carrying value of loan payable, current portion	4,686,388		3,664,370
Carrying value of loan payable, non-current portion	10,334,029		9,244,874
Total loan payable	15,020,417
CIRM [Member]
Debt Instrument [Line Items]
Carrying value of loan payable (current and non-current) Beginning Balance	3,820,264
Additional loan proceeds	5,775,543
Repayment of principal
Accretion of discount
Carrying value of loan payable (current and non-current) Ending Balance	9,595,807
Carrying value of loan payable, current portion	679,166
Carrying value of loan payable, non-current portion	8,916,641
Total loan payable	9,595,807
Silicon Valley Bank [Member]
Debt Instrument [Line Items]
Carrying value of loan payable (current and non-current) Beginning Balance	9,088,980
Additional loan proceeds		9,900,000
Repayment of principal	-3,857,971
Accretion of discount	193,601
Carrying value of loan payable (current and non-current) Ending Balance	5,424,610
Carrying value of loan payable, current portion	4,007,222
Carrying value of loan payable, non-current portion	1,417,388
Total loan payable	$5,424,610

Common_Stock_Additional_Inform

Common Stock - Additional Information (Detail) (USD $)	1 Months Ended		12 Months Ended			1 Months Ended		6 Months Ended	1 Months Ended
	Jul. 31, 2014	Oct. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2013	Nov. 30, 2008	Jun. 30, 2012	Dec. 31, 2012	Dec. 31, 2011
Subsidiary, Sale of Stock [Line Items]
Common stock issued in public offering	11,299,435	12,845,500
Sale of common stock and warrant, price per share	$1.77	$1.45		$1.91	$2.12
Proceeds from issuance of common stock and warrants	$20,000,000	$17,300,000
Warrant exercise price	$2.17	$1.80
Warrant expiration period	13 months	5 years
Gross proceeds			1,974,931	530,097	6,256,438
Percentage of compensation paid to sales agent				3.00%	3.00%
Gross proceeds from common stock			18,949,647	23,491,597	19,747,550
Common stock, par value		$0.01	$0.01	$0.01
Warrants termination agreement			2013-10
Common stock, sold				1,733,771	9,647,471
Institutional Investors [Member]
Subsidiary, Sale of Stock [Line Items]
Shares available to sale						30,000,000
Gross proceeds from common stock						3,000,000
Exercise period of rights						3 years
Additional amounts of common stock to sell						27,000,000
Outstanding Warrants [Member]
Subsidiary, Sale of Stock [Line Items]
Number of shares of common stock or warrant in each unit sold to institutional investors	1	1					1
Series A Warrants [Member]
Subsidiary, Sale of Stock [Line Items]
Warrant exercise price			$1.40
Proceeds from sale of stock			1,652,000	538,000	3,078,000
Series A Warrants [Member]
Subsidiary, Sale of Stock [Line Items]
Number of shares exercise			1,180,015
Gross proceeds			1,652,000
Series B Warrant [Member]
Subsidiary, Sale of Stock [Line Items]
Gross proceeds								3,375,000
Number of warrants exercised								2,700,000
Number of warrants expired					5,300,000
Warrant expiration date					2-May-12
Series A Warrants [Member]
Subsidiary, Sale of Stock [Line Items]
Gross proceeds					3,078,000
Number of warrants exercised			1,180,015
Number of warrants exercised					2,198,571
Number of warrants issued								2,700,000
December 2011 Financing [Member] | Series A Warrants [Member]
Subsidiary, Sale of Stock [Line Items]
Numbers of share issued										8,000,000
Number of warrants exercised				384,534
Number of warrants exercised			1,180,015	384,534	2,198,571
Number of shares issued upon warrants exercise					2,700,000
December 2011 Financing [Member] | Series A Warrants [Member]
Subsidiary, Sale of Stock [Line Items]
Number of securities callable by each warrant or right warrants			1
Numbers of share issued										8,000,000
2012 Amended Sales Agreement [Member]
Subsidiary, Sale of Stock [Line Items]
Percentage of compensation paid to sales agent			2.00%
Shares available to sale									30,000,000
Gross proceeds from common stock			$285,000
Common Stock [Member]
Subsidiary, Sale of Stock [Line Items]
Number of shares of common stock or warrant in each unit sold to institutional investors	1	1
Number of securities callable by each warrant or right warrants	0.85	0.5
Numbers of share issued			1,180,015
Number of shares issued upon warrants exercise					2,198,571			2,700,000
Common Stock [Member] | Institutional Investors [Member]
Subsidiary, Sale of Stock [Line Items]
Common stock issued in public offering						329,131
Common stock, sold						1,645,639
Sale of stock, price per share						$1.82
Common Stock [Member] | December 2011 Financing [Member]
Subsidiary, Sale of Stock [Line Items]
Common stock issued in public offering				384,534	2,700,000
Number of securities callable by each warrant or right warrants			1
Number of shares issued upon warrants exercise			1,180,015	384,534	2,198,571
Common Stock [Member] | December 2011 Financing [Member] | Series A Warrants [Member]
Subsidiary, Sale of Stock [Line Items]
Warrant exercise price										1.4
Common Stock [Member] | December 2011 Financing [Member] | Series A Warrants [Member]
Subsidiary, Sale of Stock [Line Items]
Warrant exercise price										1.4
Common Stock [Member] | 2012 Amended Sales Agreement [Member]
Subsidiary, Sale of Stock [Line Items]
Common stock, sold			193,271
Sale of stock, price per share			$1.47

Common_Stock_Reserved_Shares_o

Common Stock - Reserved Shares of Common Stock for Exercise of Options, Warrants and Other Contingent Issuances of Common Stock (Detail)	Dec. 31, 2014
Class of Stock [Line Items]
Share reserved for share-based compensation	36,438,871
Outstanding Warrants [Member]
Class of Stock [Line Items]
Share reserved for share-based compensation	23,078,181
Stock Compensation Plan [Member]
Class of Stock [Line Items]
Share reserved for share-based compensation	13,360,690

Deferred_Revenue_Additional_In

Deferred Revenue - Additional Information (Detail) (Nonsoftware License Arrangement [Member], Stem Cell Therapeutics [Member], USD $)	12 Months Ended
	Dec. 31, 2014
Nonsoftware License Arrangement [Member] | Stem Cell Therapeutics [Member]
Deferred Revenue Arrangement [Line Items]
Number of year up front license fee being amortized	12 years
Unamortized amount of deferred revenue	$63,000

401k_Plan_Additional_Informati

401(k) Plan - Additional Information (Detail) (401 (k) Plan [Member], USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
401 (k) Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer Contribution to plan	50.00%
Percentage of employee eligible for compensation in the form of shares	6.00%
Contributions expense	$184,000	$132,000	$130,000

Income_Taxes_Loss_Before_Incom

Income Taxes - Loss Before Income Tax Attributable to Geographic Location (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
United States	$30,215,000	$26,080,000
Foreign	2,526,000	359,000
Total loss before income taxes	$32,741,000	$26,439,000

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Contingency [Line Items]
Unrecognized tax benefits	$0		$0
Increase in valuation allowances	10,657,000	10,270,000
Tax liabilities	0
Tax related interest	0
Tax related penalties	0
Domestic Tax Authority [Member]
Income Tax Contingency [Line Items]
Net operating loss carry forward	158,465,000
Operating loss carryforward expiration period description	2018 through 2034
Excess deductions from exercise of stock option	1,792,000
State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Net operating loss carry forward	40,241,000
Operating loss carryforward expiration period description	2015 through 2034
Operating loss carry forward for the exercise of stock	1,362,000
Foreign Tax Authority [Member]
Income Tax Contingency [Line Items]
Net operating loss carry forward	8,208,000
Capital Loss Carryforward [Member] | Domestic And State [Member]
Income Tax Contingency [Line Items]
Operating loss carryforward expiration period description	2015 through 2016
Capital loss carry forward for federal and state income tax purposes	746,000
Research and Development [Member] | Domestic Tax Authority [Member]
Income Tax Contingency [Line Items]
Operating loss carryforward expiration period description	2018 through 2034
Capital loss carry forward for federal and state income tax purposes	6,178,000
Research and Development [Member] | State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Capital loss carry forward for federal and state income tax purposes	5,484,000
State research and development tax credits net of federal tax effect	$3,619,000

Income_Taxes_Components_of_Def

Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Capitalized research and development costs	$66,212,000	$59,426,000
Net operating losses	57,261,000	56,906,000
Research and development credits	9,798,000	8,931,000
Stock-based compensation	1,124,000	1,063,000
Capital loss carryover	254,000	541,000
Fixed assets	393,000	452,000
Other	3,930,000	1,289,000
Gross deferred tax assets	138,972,000	128,608,000
Valuation allowance	-138,972,000	-128,315,000
Total deferred tax assets		293,000
Deferred tax liability:
Intangible assets		-293,000
Total deferred tax liability		-293,000
Net deferred tax assets	$0	$0

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of Federal Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Statutory federal income tax (benefit) rate	-34.00%	-34.00%	-34.00%
State income tax (benefit) rate			-3.30%
Increase resulting from:
Expenses not deductible for taxes	0.80%	0.50%	8.80%
Increase in valuation allowance	32.60%	38.80%	3.70%
Change in state deferred tax rate	0.00%	1.10%	17.70%
Change in foreign deferred tax rate	2.80%	0.90%	1.80%
Expiration of tax attributes	1.70%	0.50%	5.30%
Prior year true up	1.10%	-0.70%
Tax credits	-2.40%	-3.00%
Warrant valuation	-2.50%	-4.10%
Effective tax (benefit) rate	0.00%	0.00%	0.00%

Discontinued_Operations_Additi

Discontinued Operations - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Proceeds from sale of indefinite intangible assets	$400,000	$400,000
Proceeds from sale of tangible assets		75,000
Net loss on disposal of assets	($111,000)	($111,254)

Quarterly_Financial_Data_Summa

Quarterly Financial Data - Summary of Quarterly Financial Data (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Continuing operations:
Total revenue	$883,000	$82,000	$23,000	$24,000	$45,000	$38,000	$33,000	$56,000
Operating expenses	10,612,000	6,462,000	7,983,000	6,866,000	9,341,000	6,628,000	6,131,000	6,165,000	31,922,705	28,264,996	22,398,175
Change in fair value of warrant liability	2,327,000	4,076,000	-3,654,000	-327,000	2,828,000	-144,000	758,000	-189,000	-2,422,451	-3,253,253	5,944,571
Impairment of goodwill and other intangible assets	-2,440,000								530,100
Interest and other income (expense), net	-266,000	-316,000	-357,000	-394,000	-380,000	-392,000	-405,000	30,000
Net loss from continuing operations	-10,108,000	-2,620,000	-11,971,000	-7,562,000	-6,848,000	-7,126,000	-5,745,000	-6,268,000	-32,260,663	-25,986,692	-27,971,259
Discontinued operations:
Net loss from discontinued operations	-30,000	-137,000	-144,000	-58,000	-115,000	-66,000	-124,000	-149,000	-369,357	-452,467	-519,894
Net loss from disposal of assets	($111,000)								($111,254)
Basic and diluted net loss per share:
Continuing operations	($0.15)	($0.04)	($0.21)	($0.14)	($0.13)	($0.17)	($0.14)	($0.16)	($0.52)	($0.60)	($0.97)
Discontinued operations	$0	$0	$0	$0	$0	$0	($0.01)	($0.01)	($0.01)	($0.01)	($0.02)
Basic and diluted net loss per share	($0.15)	($0.04)	($0.21)	($0.14)	($0.13)	($0.17)	($0.15)	($0.17)	($0.53)	($0.61)	($0.99)