Microbot Medical (MBOT) 10-K 13 Mar 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2013	Mar. 03, 2014	Jun. 30, 2013
Document And Entity Information [Abstract]	'	'	'
Document Type	'10-K	'	'
Amendment Flag	'false	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
Trading Symbol	'STEM	'	'
Entity Registrant Name	'STEMCELLS INC	'	'
Entity Central Index Key	'0000883975	'	'
Current Fiscal Year End Date	'--12-31	'	'
Entity Well-known Seasoned Issuer	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Filer Category	'Smaller Reporting Company	'	'
Entity Common Stock, Shares Outstanding	'	55,419,116	'
Entity Public Float	'	'	$66,836,311

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
Current assets:	'	'
Cash and cash equivalents	$30,585,424	$8,471,275
Marketable securities, current	'	13,900,678
Trade receivables	108,815	110,159
Other receivables	486,222	200,788
Prepaid assets	530,037	537,590
Deferred financing costs, current	46,420	'
Other current assets	83,537	820,827
Total current assets	31,840,455	24,041,317
Property, plant and equipment, net	5,304,684	1,375,329
Other assets, non-current	413,717	947,301
Goodwill	2,139,294	1,983,426
Other intangible assets, net	1,835,717	1,822,904
Deferred financing costs, non-current	23,307	'
Total assets	41,557,174	30,170,277
Current liabilities:	'	'
Accounts payable	1,151,903	999,365
Accrued expenses and other current liabilities	4,067,916	2,707,441
Accrued wind-down expenses, current	'	1,102,762
Deferred revenue, current	67,245	74,426
Capital lease obligation, current	21,316	6,888
Deferred rent, current	34,366	'
Bonds payable, current	125,000	206,250
Loan payable net of discount, current	3,664,370	'
Total current liabilities	9,132,116	5,097,132
Capital lease obligation, non-current	29,422	12,646
Bonds payable, non-current	'	125,000
Fair value of warrant liability	5,541,809	9,265,365
Other long-term liabilities	801,388	216,439
Loan payable net of discount, non-current	9,244,874	'
Deferred rent, non-current	1,790,943	1,389,342
Deferred revenue, non-current	62,910	79,736
Total liabilities	26,603,462	16,185,660
Commitments and contingencies (Note 12)	'	'
Stockholders' equity:	'	'
Common stock, $0.01 par value; 225,000,000 shares authorized; issued and outstanding 55,138,311 at December 31, 2013 and 37,506,305 at December 31, 2012	551,383	375,063
Additional paid-in capital	401,680,562	374,507,552
Accumulated deficit	-387,530,334	-361,091,175
Accumulated other comprehensive income	252,101	193,177
Total stockholders equity	14,953,712	13,984,617
Total liabilities and stockholders equity	$41,557,174	$30,170,277

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
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	55,138,311	37,506,305
Common stock, shares outstanding	55,138,311	37,506,305

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue:	'	'	'
Revenue from licensing agreements, grants and other	$205,302	$511,558	$557,880
Revenue from product sales	997,968	856,397	662,790
Total revenue	1,203,270	1,367,955	1,220,670
Cost of product sales	316,628	263,188	214,811
Gross profit	886,642	1,104,767	1,005,859
Operating expenses:	'	'	'
Research and development	20,533,713	15,846,829	19,937,764
Selling, general and administrative	8,896,537	7,447,235	8,202,375
Wind-down expenses	61,837	356,379	287,122
Impairment of intangible asset	'	'	654,961
Total operating expenses	29,492,087	23,650,443	29,082,222
Operating loss	-28,605,445	-22,545,676	-28,076,363
Other income (expense):	'	'	'
Realized gain on sale of marketable securities	'	'	83,750
Change in fair value of warrant liability	3,253,253	-5,944,571	6,612,092
Interest income	11,318	15,594	13,942
Interest expense	-1,166,782	-50,193	-71,363
Other income	68,497	33,693	109,404
Total other income (expense), net	2,166,286	-5,945,477	6,747,825
Net loss	($26,439,159)	($28,491,153)	($21,328,538)
Basic and diluted net loss per share	($0.61)	($0.99)	($1.50)
Shares used to compute basic and diluted loss per share	43,422,001	28,824,417	14,187,885

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Loss (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement Of Comprehensive Income [Abstract]	'	'	'
Net loss	($26,439,159)	($28,491,153)	($21,328,538)
Other comprehensive income (loss)	'	'	'
Foreign currency translation adjustments	57,568	151,125	40,032
Unrealized gains (losses) on marketable securities	1,356	1,339	-119,041
Other comprehensive income (loss)	58,924	152,464	-79,009
Comprehensive loss	($26,380,235)	($28,338,689)	($21,407,545)

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, 2010	$15,480,629	$127,313	$326,505,080	($311,271,486)	$119,722
Beginning Balance, Shares at Dec. 31, 2010	'	12,731,287	'	'	'
Net loss	-21,328,538	'	'	-21,328,536	'
Unrealized gain on foreign currency translation	40,032	'	'	'	40,032
Change in unrealized loss on securities available-for-sale	-119,041	'	'	'	-119,041
Issuance of common stock and warrants, net of issuance cost of $1,522,083, $900,992 and $2,051,699 in 2011,2012 and 2013 respectively	13,792,340	95,251	13,697,089	'	'
Issuance of common stock and warrants, net of issuance cost of $1,522,083, $900,992 and $2,051,699 in 2011, 2012 and 2013 respectively, shares	'	9,525,116	'	'	'
Common stock issued pursuant to employee benefit plan	164,896	352	164,544	'	'
Common stock issued pursuant to employee benefit plan, shares	'	35,164	'	'	'
Compensation expense from grant of options and restricted stock units (fair value)	3,096,043	326	3,095,717	'	'
Compensation expense from grant of options and restricted stock units (fair value), shares	'	32,631	'	'	'
Exercise of employee and director stock options	2,386	17	2,369	'	'
Exercise of employee and director stock options, shares	1,692	1,692	'	'	'
Exercise and net settlement of restricted stock units	-403,625	1,021	-404,646	'	'
Exercise and net settlement of restricted stock units, shares	'	102,065	'	'	'
Ending Balance at Dec. 31, 2011	10,725,124	224,280	343,060,153	-332,600,022	40,713
Ending 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 $1,522,083, $900,992 and $2,051,699 in 2011,2012 and 2013 respectively	28,725,507	145,460	28,580,047	'	'
Issuance of common stock and warrants, net of issuance cost of $1,522,083, $900,992 and $2,051,699 in 2011, 2012 and 2013 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 and restricted stock units (fair value)	2,655,884	1,825	2,654,059	'	'
Compensation expense from grant of options and restricted stock units (fair value), shares	'	182,502	'	'	'
Exercise of employee and director stock options	3,629	36	3,593	'	'
Exercise of employee and 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 $1,522,083, $900,992 and $2,051,699 in 2011,2012 and 2013 respectively	24,879,573	169,385	24,710,188	'	'
Issuance of common stock and warrants, net of issuance cost of $1,522,083, $900,992 and $2,051,699 in 2011, 2012 and 2013 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 and restricted stock units (fair value)	2,322,489	'	2,322,489	'	'
Compensation expense from grant of options and restricted stock units (fair value), shares	'	'	'	'	'
Exercise of employee and director stock options	3,452	35	3,417	'	'
Exercise of employee and 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	'	'	'

Consolidated_Statement_of_Stoc1

Consolidated Statement of Stockholders' Equity (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Issuance cost on issuance of common stock and warrants	($2,051,699)	$900,992	$1,522,083
Common Stock [Member]	'	'	'
Issuance cost on issuance of common stock and warrants	-2,051,699	900,992	1,522,083
Additional Paid-in Capital [Member]	'	'	'
Issuance cost on issuance of common stock and warrants	($2,051,699)	$900,992	$1,522,083

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Cash flows from operating activities:	'		'		'
Net loss	($26,439,159)		($28,491,153)		($21,328,538)
Adjustments to reconcile net loss to net cash used in operating activities:	'		'		'
Depreciation and amortization	1,058,725		991,721		1,207,911
Amortization of debt discount and issuance costs	288,951		'		'
Stock-based compensation for employees and external services	2,608,670		2,878,134		3,260,937
Loss (gain) on disposal of fixed assets	-38,854		20,883		32,145
Write-down of fixed assets	'		27,500		'
Impairment of intangible asset	'		'		654,961
Gain on sale of marketable securities	'		'		-83,750
Change in fair value of warrant liability	-3,253,253		5,944,571		-6,612,092
Changes in operating assets and liabilities:	'		'		'
Other receivables	-298,734		39,825		-78,503
Trade receivables	3,606		-50,451		67,974
Prepaid and other current assets	801,611		22,232		495,662
Other assets	493,584		89,790		76,187
Accounts payable and accrued expenses	2,143,917		-409,333		130,766
Accrued wind-down expenses	-1,102,762		-1,032,024		-1,165,585
Deferred revenue	-24,270		13,389		-18,903
Deferred rent	435,967		85,572		1,302,543
Net cash used in operating activities	-23,322,001		-19,869,344		-22,058,283
Cash flows from investing activities:	'		'		'
Purchases of marketable debt securities	-687,798		-16,380,748		-10,188,285
Sales or maturities of marketable debt securities	14,430,000		5,762,000		6,905,000
Proceeds from sales of marketable equity securities	'		'		158,206
Purchases of property, plant and equipment	-4,680,796		-73,083		-296,933
Proceeds from sale of property, plant and equipment	38,500		'		'
Acquisition of other assets	-64,000		'		'
Net cash provided by (used) in investing activities	9,035,906		-10,691,831		-3,422,012
Cash flows from financing activities:	'		'		'
Proceeds from issuance of common stock, net	23,491,597		19,747,550		19,774,820
Proceeds from the exercise of warrants	530,097		6,256,438		'
Proceeds from the exercise of stock options	3,452		3,629		2,386
Proceeds from loan payable, net of issuance costs	13,558,358		'		'
Payments related to net share issuance of stock based awards	-342,366		-59,090		-403,625
Repayments of capital lease obligations	-12,396		-20,167		-67,847
Repayments of debt obligations	-826,465		-191,250		-176,250
Net cash provided by financing activities	36,402,277		25,737,110		19,129,484
Increase (decrease) in cash and cash equivalents	22,116,182		-4,824,065		-6,350,811
Cash and cash equivalents at beginning of year	8,471,275		13,311,261		19,707,821
Effects of foreign currency rate changes on cash	-2,033		-15,921		-45,749
Cash and cash equivalents at end of the year	30,585,424		8,471,275		13,311,261
Supplemental disclosure of cash flow information:	'		'		'
Interest paid	427,040		50,193		71,363
Supplemental schedule of non-cash investing and financing activities:	'		'		'
Stock issued for an option agreement	'		50,000	[1]	'
Equipment acquired under a capital lease	43,600	[2]	21,721	[2]	'
Equity Financing Agreement [Member]	'		'		'
Supplemental schedule of non-cash investing and financing activities:	'		'		'
Fair value of shares issued as consideration	600,006	[3]	'		'
Acquired Patent Portfolio [Member]	'		'		'
Supplemental schedule of non-cash investing and financing activities:	'		'		'
Fair value of shares issued as consideration	$200,000	[4]	'		'
[1]	In September 2012, we issued 24,753 shares of restricted common stock under the terms of an agreement with a developer of biological materials in return for certain product rights including an exclusive right of first offer to commercialize the developer's products as may be developed on or before April 18, 2017.
[2]	Represents the present value of future minimum capital lease payments for equipment leased.
[3]	In June 2013, we entered into an agreement with an institutional investor, under which we have the right to sell up to $30.0 million of common stock to the institutional investor. In consideration for entering into the agreement, we issued 329,131 shares of our common stock to the institutional investor. We will not receive any cash proceeds from the issuance of these 329,131 shares. All shares sold or to be sold under this agreement are offered under our shelf registration statement previously filed with, and declared effective by, the SEC. In October 2013, we terminated the agreement without any cost or penalty.
[4]	In October, 2013, we acquired from NeuroSpheres a patent portfolio we licensed on an exclusive worldwide basis, including the six patents that are the subject of our patent infringement litigation against Neuralstem. As consideration for the patents, we issued 139,548 shares of unregistered common stock with a fair value of $200,000 to NeuroSpheres. In connection with the patent acquisition, all preexisting agreements were terminated. The acquisition relieves us from further milestone and royalty payments to NeuroSpheres.

Consolidated_Statements_of_Cas1

Consolidated Statements of Cash Flows (Parenthetical) (USD $)	9 Months Ended	1 Months Ended
	Sep. 30, 2012	Jun. 30, 2013	Dec. 31, 2013		Dec. 31, 2013
		Equity Financing Agreement [Member]	Equity Financing Agreement [Member]		Acquired Patent Portfolio [Member]
Number of shares issued as consideration	'	'	329,131	[1]	139,548	[2]
Right to sell of common stock	'	$30,000,000	'		'
Restricted Common Stock issued to developer of biological material	24,753	'	'		'
Fair value of common Stock	$200,000	'	'		'
[1]	In June 2013, we entered into an agreement with an institutional investor, under which we have the right to sell up to $30.0 million of common stock to the institutional investor. In consideration for entering into the agreement, we issued 329,131 shares of our common stock to the institutional investor. We will not receive any cash proceeds from the issuance of these 329,131 shares. All shares sold or to be sold under this agreement are offered under our shelf registration statement previously filed with, and declared effective by, the SEC. In October 2013, we terminated the agreement without any cost or penalty.
[2]	In October, 2013, we acquired from NeuroSpheres a patent portfolio we licensed on an exclusive worldwide basis, including the six patents that are the subject of our patent infringement litigation against Neuralstem. As consideration for the patents, we issued 139,548 shares of unregistered common stock with a fair value of $200,000 to NeuroSpheres. In connection with the patent acquisition, all preexisting agreements were terminated. The acquisition relieves us from further milestone and royalty payments to NeuroSpheres.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	Note 1. Summary of Significant Accounting Policies
	Nature of Business
	StemCells, Inc., a Delaware corporation, is a biopharmaceutical company that operates in one segment, the research, development, and commercialization of 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 $388 million at December 31, 2013. 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, and Stem Cell Sciences (UK) Ltd. All significant intercompany accounts and transactions have been eliminated.
	Use of Estimates
	The preparation of financial statements in conformity with 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
		•		the fair value of intangible assets acquired (see Note 5, “Goodwill and Other Intangible Assets”).
	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. Our marketable debt and equity securities are accounted for as available-for-sale. Management determines the appropriate classification of its investments in marketable debt and equity securities at the time of purchase and reevaluates the available-for-sale designations as of each balance sheet date. These securities are carried at fair value (see Note 2, “Financial Instruments,” below), with the unrealized gains and losses reported as a component of stockholders’ equity. The cost of securities sold is based upon the specific identification method.
	If the estimated fair value of a security is below its carrying value, we evaluate whether we have the intent and ability to retain our investment for a period of time sufficient to allow for any anticipated recovery to the cost of the investment, and whether evidence indicating that the cost of the investment is recoverable within a reasonable period of time outweighs evidence to the contrary. Other-than-temporary declines in estimated fair value of all marketable securities are charged to “Other income (expense), net.”
	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.
	Estimated Fair Value of Financial Instruments
	The estimated fair values of cash and cash equivalents, receivables, accounts payable, and the current portion of the bonds payable approximates their carrying values due to the short maturities of these instruments. The long-term portion of the bonds payable approximates its carrying value as the interest rate for the bond series approximates our current borrowing rate.
	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.
	Business Combinations
	The operating results of acquired companies or operations are included in our consolidated financial statements starting on the date of acquisition. Goodwill is recorded at the time of an acquisition and is calculated as the difference between the aggregate consideration paid for an acquisition and the fair value of the net tangible and intangible assets acquired. Accounting for acquisitions requires extensive use of accounting estimates and judgments to allocate the purchase price to the fair value of the net tangible and intangible assets acquired, including in-process research and development (IPR&D).
	Goodwill and Other Intangible Assets (Patent and License Costs)
	Goodwill of approximately $2,139,000 at December 31, 2013, relates to the acquisition of SCS operations. Goodwill and intangible assets deemed to have indefinite lives are not amortized but are subject to annual impairment tests. If the assumptions and estimates used to allocate the purchase price are not correct, or if business conditions change, purchase price adjustments or future asset impairment charges could be required. We test goodwill for impairment on an annual basis or more frequently if we believe indicators of impairment exist. Impairment evaluations involve management estimates of asset useful lives and future cash flows. Significant management judgment is required in the forecasts of future operating results that are used in the evaluations, and it is possible, even likely, that the plans and estimates used may be incorrect. If our actual results, or the plans and estimates used in future impairment analysis are lower than the original estimates used to assess the recoverability of these assets, we could incur additional impairment charges in a future period. We completed our annual impairment testing during the fourth quarter of 2013, and determined that there was no impairment of goodwill.
	Other intangible assets, net were approximately $1,836,000 at December 31, 2013. Intangible assets with finite useful lives are amortized generally on a straight-line basis over the periods benefited. Intangible assets are 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.
	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 2011 and 2013.
	Warrant Liability
	We account for our warrants in accordance with U.S. GAAP which defines how freestanding contracts that are indexed to and potentially settled in a company’s own stock should be measured and classified. Authoritative accounting guidance prescribes that only warrants issued by us under contracts that cannot be net-cash settled, and are both indexed to and settled in our common stock, can be classified as equity. As part of both our November 2008 and November 2009 financings, we issued warrants with five year terms to purchase 1,034,483 and 400,000 shares of our common stock at $23.00 and $15.00 per share, respectively. As part of our December 2011 financing, we issued Series A Warrants with a five year term to purchase 8,000,000 shares at $1.40 per share and Series B Warrants with a ninety trading day term to purchase 8,000,000 units at $1.25 per unit. Each unit underlying the Series B Warrants consisted of one share of our common stock and one Series A Warrant. In the first and second quarter of 2012, an aggregate of 2,700,000 Series B Warrants were exercised. For the exercise of these warrants, we issued 2,700,000 shares of our common stock and 2,700,000 Series A Warrants. The remaining 5,300,000 Series B Warrants expired unexercised by their terms on May 2, 2012. As terms of the warrants issued in 2008 and 2009, as well as the Series A and Series B Warrants, do not meet the specific conditions for equity classification, we are required to classify the fair value of these warrants as a liability, with subsequent changes in fair value to be recorded as income (loss) due to change in fair value of warrant liability. The fair value of the warrants issued in the 2008 and 2009 financings is determined using the Black-Scholes-Merton (Black-Scholes) option pricing model and the fair value of the Series A and Series B Warrants is determined using a Monte Carlo simulation model (see Note 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, 2013, was approximately $5,542,000.
	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. Product sales are presented net of any sales or value-added taxes.
	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. We reported as a long-term liability on our balance sheet, a net deferred tax liability of approximately $118,000 that is related to an indefinite-lived intangible acquired as part of the SCS operations.
	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:
			2013			2012			2011
	Net loss		$	(26,439,159	)	$	(28,491,153	)	$	(21,328,536	)
	Weighted average shares outstanding used to compute basic and diluted net loss per share			43,422,001			28,824,417			14,187,885
	Basic and diluted net loss per share		$	(0.61	)	$	(0.99	)	$	(1.50	)
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:
		2013			2012			2011
Outstanding options			428,258			447,359			875,498
Restricted stock units			3,326,282			1,534,200			357,541
Outstanding warrants			16,267,659			9,935,912			17,434,483
Total			20,022,199			11,917,471			18,667,522
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:
		2013			2012
Net unrealized gain (loss) on marketable securities		$	—		$	(1,356	)
Unrealized gain on foreign currency translation			252,101			194,533
Accumulated other comprehensive income		$	252,101		$	193,177
Recent Accounting Pronouncements
In July 2013, the Financial Accounting Standards Board (FASB) issued ASU 2013-11 “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists”, an update to Topic 740, Income Taxes. This Update applies to all entities that have unrecognized tax benefits when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists at the reporting date. The amendments in this Update are expected to reduce diversity in practice by providing guidance on the presentation of unrecognized tax benefits and to better reflect the manner in which an entity would settle at the reporting date any additional income taxes that would result from the disallowance of a tax position when net operating loss carryforwards, similar tax losses, or tax credit carryforwards exist. This update is effective for annual and interim reporting periods for fiscal years beginning after December 15, 2013. The adoption of the amended standard is not expected to have a material impact on our consolidated financial statements.

Financial_Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2013
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, cash equivalents and available-for-sale securities held in our investment portfolio:
		Amortized		Gross		Gross			Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	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
	December 31, 2012
	Cash	$	254,267	$	—	$	—		$	254,267
	Cash equivalents (money market accounts)		8,217,259		—		(252	)		8,217,007
	Marketable debt securities, current		13,901,782		—		(1,104	)		13,900,678
	Total cash, cash equivalents, and marketable securities	$	22,373,308	$	—	$	(1,356	)	$	22,371,952
	At December 31, 2013, our investments in money market accounts are through a money market fund that invests in high quality, short-term money market instruments which are classified as cash equivalents in the accompanying Consolidated Balance Sheet due to their short maturities. The investment seeks to provide the highest possible level of current income while still maintaining liquidity and preserving capital. From time to time, we carry cash balances in excess of federally insured limits. Our cash balance at December 31, 2013 includes approximately $146,000 held by our U.K. subsidiary.
	We do not hold any investments that were in a material unrealized loss position as of December 31, 2013.

Fair_Value_Measurement

Fair Value Measurement	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurement	'
	Note 3. Fair Value Measurement
	Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. As a basis for considering such assumptions, we are required to apply a three-tier value hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value. The three levels of the fair value hierarchy are:
	Level 1 — Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets.
	Level 2 — Directly or indirectly observable inputs other than in Level 1, that include quoted prices for similar assets or liabilities in active markets or quoted prices for identical or similar assets or liabilities in markets that are not active.
	Level 3 — Unobservable inputs which are supported by little or no market activity that reflects the reporting entity’s own assumptions about the assumptions that market participants would use in pricing the asset or liability.
	The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Assets measured at fair value as of December 31, 2013 and 2012 are classified below based on the three fair value hierarchy tiers described above.
	Our cash equivalents are classified as Level 1 because they are valued primarily using quoted market prices.
	Our bonds payable, marketable securities, and liability for warrants issued in our 2008 and 2009 financing, are classified as Level 2 as they are valued using alternative pricing sources and models utilizing market observable inputs.
	We estimated the fair value of our loan payable using the net present value of the payments discounted at an effective interest rate. We believe the estimates used to measure the fair value of our loan payable constitute Level 3 inputs.
	Our liability for warrants issued in our 2011 financing is classified as Level 3 as the liability is valued using a Monte Carlo simulation model. Some of the significant inputs used to calculate the fair value of warrant liability include our stock price on the valuation date, expected volatility of our common stock as traded on NASDAQ, and risk-free interest rates that are derived from the yield on U.S. Treasury debt securities, all of which are observable from active markets. However, the use of a Monte Carlo simulation model requires the input of additional subjective assumptions including management’s assumptions regarding the likelihood of a re-pricing of these warrants pursuant to anti-dilution provisions and the progress of our R&D programs and its affect on potential future financings.
	The following table presents our financial assets and liabilities measured at fair value:
		Fair Value Measurement						Unobservable
		at Reporting Date Using						Inputs
		Quoted Prices			Significant Other			(Level 3)			As of
		in Active Markets for			Observable Inputs						December 31,
		Identical Assets			(Level 2)						2013
		(Level 1)
	Financial assets
	Cash equivalents:
	Money market funds	$	821,335		$	—		$	—		$	821,335
	U.S. Treasury debt obligations		28,408,808			—			—			28,408,808
	Total financial assets	$	29,230,143		$	—		$	—		$	29,230,143
	Financial liabilities
	Bond obligation	$	—		$	125,000		$	—		$	125,000
	Loan payable net of discounts		—			—			12,909,244			12,909,244
	Warrant liabilities		—			—			5,541,810			5,541,810
	Total financial liabilities	$	—		$	125,000		$	18,451,054		$	18,576,054
	Level 2 Reconciliation
	The following table presents a roll forward for financial assets and liabilities measured at fair value using significant other observable inputs (Level 2) for 2013.
		Level 2			Net transfers (to)			Change			Settled			Level 2
		Beginning			from			included in			$			Ending
		Balance 12/31/12			Level 1			earnings						Balance 12/31/13
		$			$			$						$
	Marketable debt securities		13,900,678			(13,900,678	)		—			—			—
	Bond obligation		331,250			—			—			(206,250	)		125,000
	Warrant liabilities		107,968			—			(107,968	)		—			—
	Transfers from Level 2 to Level 1 for marketable debt securities are maturities of short term marketable debt securities into cash and cash equivalents.
	Level 3 Reconciliation
	The following table presents a roll forward for liabilities measured at fair value using significant unobservable inputs (Level 3) for 2013.
		Warrant
		Liabilities
	Balance at December 31, 2012	$	9,157,397
	Less fair value of warrants exercised		(470,303	)
	Add change in fair value of warrants		(3,145,285	)
	Balance at December 31, 2013	$	5,541,809
		Loan
		Payable
	Balance at December 31, 2012	$	—
	Add loan proceeds		13,820,264
	Less discount		(487,576	)
	Initial carrying value	$	13,332,688
	Less repayments of principal		(620,215	)
	Add accretion of discount		196,771
	Balance at December 31, 2013	$	12,909,244
	Current portion	$	3,664,370
	Non-current portion		9,244,874
	Balance at December 31, 2013	$	12,909,244

Property_Plant_and_Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2013
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:
		2013			2012
	Building and improvements	$	6,751,393		$	3,441,192
	Machinery and equipment		7,837,140			6,671,866
	Furniture and fixtures		602,599			595,619
			15,191,132			10,708,677
	Less accumulated depreciation and amortization		(9,886,448	)		(9,333,348	)
	Property, plant and equipment, net	$	5,304,684		$	1,375,329
	Depreciation and amortization expense was approximately $789,000 in 2013, $728,000 in 2012, and $842,000 in 2011.

Goodwill_and_Other_Intangible_

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2013
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 Stem Cell Sciences Plc (SCS) for an aggregate purchase price of approximately $5,135,000. The acquired operations includes proprietary cell technologies relating to embryonic stem cells, induced pluripotent stem (iPS) cells, and tissue-derived (adult) stem cells; expertise and infrastructure for providing cell-based assays for drug discovery; a cell culture products business; and an intellectual property portfolio with claims relevant to cell processing, reprogramming and manipulation, as well as to gene targeting and insertion.
	At April 1, 2009, the purchase price has been 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.
	Trade name relates to the “SC Proven” trademark of our cell culture products which we expect to market for 15 years from the date of acquisition, based on which, we estimated a remaining useful life of 15 years from the valuation date.
	The following table represents changes in goodwill in 2013:
	Balance as of December 31, 2012	$	1,983,426
	Net deferred tax liability related to indefinite lived IPR&D		117,815
	Foreign currency translation		38,053
	Balance as of December 31, 2013	$	2,139,294
	The components of our other intangible assets at December 31, 2013 are summarized below:
	Other Intangible	Cost		Acquisition		Impairment			Accumulated			Foreign Currency		Net Carrying		Weighted-
	Asset Class								Amortization			Translation		Amount		Average
																Amortization
																Period
	Customer relationships and developed technology	$	1,310,000	$	—	$	—		$	(876,535	)	$	156,966	$	590,431		8.0 years
	In-process research and development		1,340,000		—		(654,961	)		(270,687	)		146,672		561,024		Indefinite
	Trade name		310,000		—		—			(107,944	)		41,748		243,804		15.0 years
	Patents		979,612		264,000		—			(803,154	)		—		440,458		17.0 years
	Total other intangible assets	$	3,939,612	$	264,000	$	(654,961	)	$	(2,058,320	)	$	345,386	$	1,835,717		12.7 years
	Amortization expense was approximately $269,000 in 2013, $264,000 in 2012, and $366,000 in 2011.
	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:
	2014	$	300,434
	2015	$	242,588
	2016	$	215,639
	2017	$	195,066
	2018	$	80,851

Other_Assets

Other Assets	12 Months Ended
	Dec. 31, 2013
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:
		2013		2012
	Prepaid royalties	$	—	$	614,488
	Security deposit (buildings and equipment lease)		413,717		332,813
	Total other non-current assets	$	413,717	$	947,301

Accounts_Payable

Accounts Payable	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Accounts Payable	'
	Note 7. Accounts Payable
	Accounts payable at December 31 are summarized below:
		2013		2012
	External services	$	863,030	$	678,813
	Supplies		263,866		216,900
	Other		25,007		103,652
	Total accounts payable	$	1,151,903	$	999,365

Accrued_Expenses_and_Other_Cur

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2013
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:
		2013		2012
	External services	$	1,191,048	$	900,580
	Employee compensation		2,655,242		1,577,322
	Other		221,626		229,539
	Total accrued expenses and other current liabilities	$	4,067,916	$	2,707,441

Other_LongTerm_Liabilities

Other Long-Term Liabilities	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Other Long-Term Liabilities	'
	Note 9. Other Long-Term Liabilities
		2013		2012
	Accrued interest on loan payable	$	497,134	$	—
	Employee compensation		186,439		216,439
	Net deferred tax liability		117,815		—
	Total accrued expenses and other current liabilities	$	801,388	$	216,439

StockBased_Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased 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, 2013, we had 8,553,608 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:
			2013			2012			2011
	Research and development expense		$	1,219,308		$	1,280,298		$	1,680,431
	General and administrative expense			1,389,362			1,597,836			1,580,506
	Total stock-based compensation expense and effect on net loss		$	2,608,670		$	2,878,134		$	3,260,937
	As of December 31, 2013, we have approximately $4,275,000 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 3.0 years.
	The fair value of options 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:
			2013			2012			2011
	Expected term (years)(1)			5.1			6.4			7.4
	Risk-free interest rate(2)			1.2	%		1.4	%		2.7	%
	Expected volatility(3)			89.3	%		78.4	%		79.7	%
	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, 2010			1,098,241		$	20.2			6.1		$	398,219
	Granted			3,750		$	7.3
	Exercised			(1,692	)	$	1.41					$	11,293
	Cancelled (forfeited and expired)			(224,801	)	$	20.22
	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		$	—
	Exercisable at December 31, 2013			409,792		$	20.42			4.2		$	—
	Vested and expected to vest(2)			426,027		$	20.02			4.3		$	—
	-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 2013 and 2012.The estimated weighted average fair value per share of options granted was approximately $5.31 in 2011, based on the assumptions in the Black-Scholes model discussed above. Total intrinsic value of options exercised at time of exercise was approximately $2,000 in 2013, $4,000 in 2012, and $11,000 in 2011.
	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, 2012			64,503		$	8.67
	Granted			—			—
	Vested			(45,564	)	$	8.91
	Cancelled			(473	)	$	7.82
	Unvested options at December 31, 2013			18,466		$	8.11
	The estimated fair value of options vested were approximately $406,000 in 2013, $627,000 in 2012 and $1,545,000 in 2011.
	The following table presents weighted average exercise price and remaining term information about significant option groups outstanding at December 31, 2013:
	Options Outstanding at December 31, 2013
	Range of		Number			Weighted Average			Weighted Average			Aggregate Intrinsic
	Exercise Prices		Outstanding			Remaining			Exercise			Value at December 31,
						Term (Yrs.)			Price			2013
	Less than $10.00			4,050			7.3		$	7.42		$	—
	$10.00 - $19.99			250,949			5.3		$	12.65			—
	$20.00 - $29.99			117,459			3.1		$	23.22			—
	$30.00 - $39.99			19,800			1.9		$	36.46			—
$40.00 - $49.99			5,500			1.7		$	46.51			—
$50.00 - $59.99			30,500			1.7		$	53.94			—
			428,258			4.3		$	19.97		$	—
Vested Options Outstanding at December 31, 2013
Range of Exercise Prices		Number			Weighted Average
		Outstanding			Exercise Price
Less than $10.00			2,677		$	7.45
$10.00 - $19.99			233,856		$	12.81
$20.00 - $29.99			117,459		$	23.22
$30.00 - $39.99			19,800		$	36.46
$40.00 - $49.99			5,500		$	46.51
$50.00 - $59.99			30,500		$	53.94
			409,792		$	20.42
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, 2013 is as follows:
		Number of			Weighted Average
		RSUs			Grant Date Fair
					Value
Outstanding at January 1, 2013			1,534,200		$	2.1
Granted(1)			2,421,965		$	1.8
Vested and exercised			(565,883	)	$	3.37
Cancelled			(64,000	)	$	1.61
Outstanding at December 31, 2013			3,326,282		$	1.68
-1	11,765 of these restricted stock units vested on the date of grant. 55,000 of these restricted stock units vest and convert into shares of our common stock after one year from the date of grant. 2,355,200 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, 2013 are fully vested. Compensation expense is based on the fair value of SARs which is calculated using the Black-Scholes option pricing model.
The stock-based compensation expense and liability are re-measured at each reporting date through the earlier of date of settlement or forfeiture of the SARs.
The following is a summary of the changes in our outstanding SARs for the last three fiscal years:
		2013						2012					2011
		Number			Weighted			Number			Weighted		Number			Weighted
					Average						Average					Average
					Exercise						Exercise					Exercise
					Price						Price					Price
Outstanding at January 1,			110,593		$	20			115,187		$	20		135,409		$	20
Granted			—			—			—			—		—			—
Exercised			—			—			—			—		—			—
Forfeited			—						(4,594	)				(20,222	)
Outstanding at December 31,			110,593		$	20			110,593		$	20		115,187		$	20
Exercisable at December 31,			110,593		$	20			110,593		$	20		115,187		$	20
For the year ended December 31, 2013, the re-measured liability related to the SARs reduced compensation expense by approximately $11,000.The total compensation expense related to SARs was approximately $18,000 in 2012 and for the year ended December 31, 2011, the re-measured liability related to the SARs reduced compensation expense by approximately $344,000. The 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, 2013
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.
	The summary of the changes to our wind-down reserve related to this facility for 2013 and 2012 were as follows:
	The components of our wind-down reserve at December 31 are as follows:
		2013			2012
	Accrued wind-down reserve at beginning of period	$	854,000		$	1,683,000
	Less actual expenses recorded against estimated reserve during the period		(916,000	)		(1,185,000	)
	Additional expense recorded to revise estimated reserve		62,000			356,000
	Revised reserve at period-end		—			854,000
	Add deferred rent at period end		—			249,000
	Total accrued wind-down expenses at period-end (current)	$	—		$	1,103,000

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2013
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 Rhode Island’s pilot manufacturing facility. 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. Interest rate for the remaining bond series is 9.5%. The outstanding principal was approximately $125,000 at December 31, 2013 and $331,000 at December 31, 2012. The bonds contain certain restrictive covenants which limit, among other things, the payment of cash dividends and the sale of the related assets.
	Operating leases
	We lease various real properties under operating leases that generally require us to pay taxes, insurance, maintenance, and minimum lease payments. Some of our leases have options to renew.
	Operating Leases — California
	In September 2010, we entered into a two-year sublease agreement with Caliper Life Sciences, Inc., for office and research space in a facility located in Mountain View, California. In June 2012, the sublease term was extended to and expired on September 30, 2013. We paid approximately $1,081,000 in aggregate as rent over the term of the lease.
	In December 2010, we entered into a commercial lease agreement with BMR-Gateway Boulevard LLC (BMR), as landlord, for office and research space at BMR’s Pacific Research Center in Newark, California. The initial term of the lease is approximately eleven and one-half years and includes escalating rent payments which we recognize as lease operating expense on a straight-line basis. We will pay approximately $17,869,000 in aggregate as rent over the term of the lease to BMR. Deferred rent for this facility was approximately $1,434,000 as of December 31, 2013, and approximately $1,389,000 as of December 31, 2012.
	In March 2013, we entered into a commercial lease agreement with Prologis, L.P. (Prologis), as landlord, for office and research space in Sunnyvale, California. The facility is for operations that support our clinical development activities. The initial term of the lease is ten years and includes escalating rent payments which we recognize as lease operating expense on a straight-line basis. We will pay approximately $3,497,000 in aggregate rent over the term of the lease. As part of the lease, Prologis has agreed to provide us financial allowances to build initial tenant improvements, subject to customary terms and conditions relating to landlord-funded tenant improvements. The tenant improvements are recorded as leasehold improvement assets and amortized over the term of the lease. The financial allowances are treated as a lease incentive and recorded as deferred rent which is amortized as reductions to lease expense over the lease term. Deferred rent for this facility was approximately $391,000 as of December 31, 2013.
	Operating Leases — Rhode Island
	We entered into a fifteen-year lease agreement for a scientific and administrative facility (SAF) in Rhode Island in connection with a sale and leaseback arrangement in 1997. The lease term expired on June 30, 2013. For the year 2013, we paid approximately $1,165,000 in operating lease payments and operating expenses net of sub-tenant income.
	Operating Leases — United Kingdom
	In January 2011, we amended the existing lease agreements of our wholly-owned subsidiary, Stem Cell Sciences (U.K.) Ltd, effectively reducing our leased office and lab space. The lease by its terms was extended to September 30, 2013. In October 2013, we signed a new three-year lease agreement for the leased space and expect to pay rent of approximately GBP 53,000 per annum. StemCells, Inc. is the guarantor of Stem Cell Sciences (U.K.) Ltd’s obligations under the existing lease. The lease includes an option for early termination of the lease agreement.
	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:
			2013			2012			2011
	Rent expense		$	2,612,899		$	2,932,104		$	4,193,433
	Sublease income			(53,726	)		(411,885	)		(424,847	)
	Rent expense, net		$	2,559,173		$	2,520,219		$	3,768,586
	Future minimum payments under all leases, bond payable and loan payable at December 31, 2013 are as follows:
			Bonds			Loan(1)			Capital			Operating
			Payable			Payable			Leases			Leases
	2014		$	136,852		$	4,322,035		$	24,284		$	1,917,423
	2015			—			4,322,035			21,591			1,912,217
	2016			—			1,440,678			9,454			1,968,459
	2017			—			—			—			2,014,706
	2018			—			—			—			2,061,260
	Thereafter			—			—			—			8,196,910
	Total minimum lease payments			136,852			10,084,748			55,329		$	18,070,975
	Less amounts representing interest			11,852			704,963			4,591
	Principal amounts of bond payable, loan payable and capital lease obligations			125,000			9,379,785			50,738
	Less current maturities			125,000			3,857,971			20,936
	Bond payable, loan payable and capital lease obligations, less current maturities		$	—		$	5,521,814		$	29,802
	-1	Approximately $3.8 million received as initial disbursement of the loan provided under the CIRM Loan Agreement is not included. In April 2013, we entered into an agreement with CIRM under which CIRM will provide up to approximately $19.3 million to help fund preclinical development and IND-enabling activities of our HuCNS-SC cells for Alzheimer’s disease. The funding is in the form of a forgivable loan, in accordance with mutually agreed upon terms and conditions and CIRM regulations, and is expected to be disbursed periodically by CIRM over the four-year project period subject to a number of preconditions, including the achievement of certain progress milestones and compliance with certain financial covenants. The loan is unsecured and the term of the loan is ten years and may be extended under certain circumstances.
	Contingencies
	In July 2006, we filed suit against Neuralstem, Inc. in the Federal District Court for the District of Maryland, alleging that Neuralstem’s activities violate claims in four of the patents we exclusively licensed from NeuroSpheres Holdings Ltd. and NeuroSpheres Ltd. (NeuroSpheres), specifically U.S. Patent No. 6,294,346 (claiming the use of human neural stem cells for drug screening), U.S. Patent No. 7,101,709 (claiming the use of human neural stem cells for screening biological agents), U.S. Patent No. 5,851,832 (claiming methods for proliferating human neural stem cells), and U.S. Patent No. 6,497,872 (claiming methods for transplanting human neural stem cells). In May 2008, we filed a second patent infringement suit against Neuralstem and its two founders, Karl Johe and Richard Garr. In this suit, which we filed in the Federal District Court for the Northern District of California, we allege that Neuralstem’s activities infringe claims in two patents we exclusively license from NeuroSpheres, specifically U.S. Patent No. 7,361,505 (claiming composition of matter of human neural stem cells derived from any source material) and U.S. Patent No. 7,115,418 (claiming methods for proliferating human neural stem cells). In addition, we allege various state law causes of action against Neuralstem arising out of its repeated derogatory statements to the public about our patent portfolio. Also in May 2008, Neuralstem filed suit against us and NeuroSpheres in the Federal District Court for the District of Maryland seeking a declaratory judgment that the ‘505 and ‘418 patents are either invalid or are not infringed by Neuralstem and that Neuralstem has not violated California state law. In August 2008, the California court transferred our lawsuit against Neuralstem to Maryland for resolution on the merits. In July 2009, the Maryland District Court granted our motion to consolidate these two cases with the litigation we initiated against Neuralstem in 2006. Discovery is ongoing in these cases.
	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 exclusively licensed by us 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 licensed to us. Neuralstem has appealed this decision.
	In October, 2013, we acquired from NeuroSpheres a patent portfolio consisting of the patents we licensed from NeuroSpheres on an exclusive worldwide basis, including the six patents that are the subject of our patent infringement litigation against Neuralstem. As consideration for the patents, we issued 139,548 shares of unregistered common stock to NeuroSpheres. In connection with the patent acquisition, all preexisting agreements were terminated. The acquisition relieves us from further milestone and royalty payments to NeuroSpheres.

Warrant_Liability

Warrant Liability	12 Months Ended
	Dec. 31, 2013
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 fair value of the warrants will continue to be classified as a liability until such time as the warrants are exercised, expire or an amendment of the warrant agreement renders these warrants to be no longer classified as a liability.
	The assumptions used for the Black-Scholes option pricing model are as follows:
		To Calculate
		Fair Value of
		Warrant Liability at
		December 31,
		2013			2012
	Expected life (years)		0.4			1.4
	Risk-free interest rate		0.1	%		0.2	%
	Expected volatility		46.1	%		108.2	%
	Expected dividend yield		0	%		0	%
		At December 31,			At December 31,			Change in Fair Value
		2013			2012			of Warrant Liability
								in Year 2013
	Fair value of warrant liability	$	—		$	44,628		$	(44,628	)
	In November 2009, we sold 1,000,000 units to institutional investors at a price of $12.50 per unit, for gross proceeds of $12,500,000. The units, each of which consisted of one share of common stock and a warrant to purchase 0.40 shares of common stock at an exercise price of $15.00 per share, were offered as a registered direct offering under a shelf registration statement previously filed with, and declared effective by, the SEC. We received total proceeds, net of offering expenses and placement agency fees, of approximately $11,985,000. We recorded the fair value of the warrants to purchase 400,000 shares of our common stock as a liability. The fair value of the warrant liability is revalued at the end of each reporting period, with the change in fair value of the warrant liability recorded as a gain or loss in our consolidated statements of operations. The fair value of the warrants will continue to be classified as a liability until such time as the warrants are exercised, expire or an amendment of the warrant agreement renders these warrants to be no longer classified as a liability.
	The assumptions used for the Black-Scholes option pricing model are as follows:
		To Calculate
		Fair Value of
		Warrant Liability at
		December 31,			December 31,
		2013			2012
	Expected life (years)		1.3			2.3
	Risk-free interest rate		0.2	%		0.3	%
	Expected volatility		48.2	%		94.5	%
	Expected dividend yield		0	%		0	%
		At December 31,			At December 31,			Change in Fair Value
		2013			2012			of Warrant Liability
								in Year 2013
	Fair value of warrant liability	$	—		$	63,340		$	(63,340	)
	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 and 2013, an aggregate of 2,198,571 and 384,534 Series A Warrants were exercised, respectively. For the exercise of these warrants, in 2012 and 2013, we issued 2,198,571 and 384,534 shares of our common stock and received gross proceeds of approximately $3,078,000 and $538,000, 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, 2013 are as follows:
	Risk-free interest rate per year		0.8	%
	Expected volatility per year		85.2	%
	Expected dividend yield		0	%
	Expected life (years)		3
	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 2013:
		Series A
		Number of			Fair value $
		Warrants
	Balance at December 31, 2012		8,501,429		$	9,157,397
	Less exercised		(384,534	)		(470,303	)
	Changes in fair value		—			(3,145,285	)
	Balance at December 31, 2013		8,116,895		$	5,541,809
	The following table is a summary of our warrant liability as of December 31, 2013:
	Warrants	Number Outstanding			Exercise Price ($)			Fair value
					per share
	Warrants issued in 2008		1,034,483			23		$	—
	Warrants issued in 2009		400,000			15			—
	Series A Warrants		8,116,895			1.4			5,541,809
	Total		9,551,378					$	5,541,809

Loan_Payable

Loan Payable	12 Months Ended
	Dec. 31, 2013
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 California Institute for Regenerative Medicine (CIRM) (the CIRM Loan Agreement) under which CIRM will provide up to approximately $19.3 million to help fund preclinical development and IND-enabling activities of our HuCNS-SC cells for Alzheimer’s disease. This funding was awarded in September 2012 under CIRM’s Disease Team Therapy Development Award program (RFA 10-05), and the goal of the research is to file an Investigational New Drug application with the U.S. Food and Drug Administration within four years. The funding is in the form of a forgivable loan, in accordance with mutually agreed upon terms and conditions and CIRM regulations, and is expected to be disbursed periodically by CIRM over the four-year project period subject to a number of preconditions, including the achievement of certain progress milestones and compliance with certain financial covenants. The loan is unsecured and the term of the loan is ten years and may be extended under certain circumstances. Initially, the loan will bear interest at the one year LIBOR rate plus two percent and will increase by 1% each year after year five. Interest will accrue with the first disbursement of loan funds, but we will not begin paying interest until year six. Repayment of the principal and any accrued and unpaid interest will be due and payable at the end of the term. We can prepay the CIRM loan at our election, either in whole or in part at any time and without a prepayment fee. In addition, the loan is forgivable so that our obligation to repay will be contingent upon the success of our HuCNS-SC cells as a treatment for Alzheimer’s disease. In July 2013 and January 2014, we received approximately $3.8 million in each month as initial and subsequent disbursement respectively of the loan provided under the CIRM Loan Agreement.
	The following table is a summary of the changes in the carrying value of our loan payable:
		Silicon Valley			CIRM Loan		Total
		Bank Loan
	Loan proceeds	$	10,000,000		$	3,820,264	$	13,820,264
	Cash discount		(100,000	)				(100,000	)
	Fair value of warrants issued		(387,576	)		—		(387,576	)
	Initial carrying value		9,512,424			3,820,264		13,332,688
	Repayment of principal		(620,215	)		—		(620,215	)
	Accretion of discount		196,771			—		196,771
	Carrying value of loan payable at 12/31/2013 (current and non-current)	$	9,088,980		$	3,820,264	$	12,909,244
	Carrying value of loan payable, current portion	$	3,664,370		$	—	$	3,664,370
	Carrying value of loan payable, non-current portion		5,424,610			3,820,264		9,244,874
	Total loan payable at 12/31/2013	$	9,088,980		$	3,820,264	$	12,909,244

Common_Stock

Common Stock	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Common Stock	'
	Note 15. Common Stock
	In December 2013, at our 2013 Annual Meeting of Stockholders, the proposal to amend our Certificate of Incorporation to increase the number of authorized shares of common stock from 75,000,000 to 225,000,000 was approved. We have neither declared nor paid dividends on any share of common stock and do not expect to do so in the foreseeable future.
	Sale of common stock
	Major transactions involving our common stock for the last three years include the following:
		•	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.
		•	In December 2011, we raised gross proceeds of $10 million 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 on the fifth anniversary of the closing date of the initial financing transaction in December 2011. The shares were offered under our effective shelf registration statement previously filed with, and declared effective by, the SEC.
		•	In January 2011, we sold 1,000,000 shares of our common stock to selected institutional investors at a price of $10.00 per share. We received net proceeds, after deducting offering expenses and fees, of approximately $9,400,000. The investors were also granted an option to purchase an additional 6,000,000 shares at $10.00 per share. The option was not exercised and expired on February 18, 2011. The shares were offered under a shelf registration previously filed with, and declared effective by, the SEC.
		•	In 2011, we sold a total of 525,116 shares of our common stock under the 2009 sales agreement at an average price per share of $2.47 for gross proceeds of approximately $1,297,000. The sales agent is paid compensation equal to 3.0% of gross proceeds pursuant to the terms of the agreement. The shares were offered under a shelf registration previously filed with, and declared effective by, the SEC.
	Stock Issued For Technology Licenses
	In October, 2013, we acquired from NeuroSpheres a patent portfolio we licensed on an exclusive worldwide basis, including the six patents that are the subject of our patent infringement litigation against Neuralstem. As consideration for the patents, we issued 139,548 shares of unregistered common stock with a fair value of $200,000 to NeuroSpheres. In connection with the patent acquisition, all preexisting agreements were terminated. The acquisition relieves us from further milestone and royalty payments to NeuroSpheres
	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, 2013:
	Shares reserved for share based compensation		12,308,148
	Shares reserved for warrants related to financing transactions		16,267,659
	Total		28,575,807

Deferred_Revenue

Deferred Revenue	12 Months Ended
	Dec. 31, 2013
Revenue Recognition [Abstract]	'
Deferred Revenue	'
	Note 16. Deferred Revenue
	Deferred revenue includes unamortized upfront licensing fees received of approximately $107,000 and prepaid orders for our SC Proven products of approximately $23,000. The up-front license fee is being amortized and recognized as revenue over a period of twelve years. Revenue from sale of our SC Proven products is recognized when shipped.

401k_Plan

401(k) Plan	12 Months Ended
	Dec. 31, 2013
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 $132,000 in 2013, $130,000 in 2012, and $165,000 in 2011 for our contributions under our 401(k) Plan.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
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,
			2013			2012
	United States		$	26,080,000		$	28,356,000
	Foreign			359,000			133,000
	Total loss before income taxes		$	26,439,000		$	28,489,000
	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, 2013 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:
			2013			2012
	Deferred tax assets:
	Capitalized research and development costs		$	59,426,000		$	53,824,000
	Net operating losses			56,906,000			53,687,000
	Research and development credits			8,931,000			7,777,000
	Accrued wind down cost			—			292,000
	Stock-based compensation			1,063,000			853,000
	Capital loss carryover			541,000			544,000
	Fixed assets			452,000			430,000
	Other			1,289,000			1,002,000
				128,608,000			118,409,000
	Valuation allowance			(128,315,000	)		(118,045,000	)
	Total deferred tax assets		$	293,000		$	364,000
	Deferred tax liability:
	Intangible assets			(293,000	)		(364,000	)
	Total deferred tax liability		$	(293,000	)	$	(364,000	)
	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 $10,270,000 in 2013 and by approximately $864,000 in 2012.
	As of December 31, 2013, we had the following:
		•		Net operating loss carry forwards for federal income tax purposes of approximately $154,541,000 which expire in the years 2018 through 2033. 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 $5,656,000 which expire in the years 2018 through 2033.
		•		Net operating loss carry forwards for state income tax purposes of approximately $43,747,000 which expire in the years 2014 through 2033. 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 $4,962,000 ($3,275,000 net of federal tax effect) which do not expire.
		•		Net operating loss carry forwards in foreign jurisdictions of approximately $11,896,000 which do not expire.
		•		Capital loss carry forwards for federal and state income tax purposes of $1,592,000 which expire in the years 2014 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:
			2013			2012			2011
	Statutory federal income tax (benefit) rate			(34	)%		(34	)%		(34	)%
	State income tax (benefit) rate			—			(3.3	)		(3.4	)
	Increase resulting from:
	Expenses not deductible for taxes			0.5			8.8			(6.7	)
	Increase in valuation allowance			38.8			3.7			32.8
	Change in state deferred tax rate			1.1			17.7			0
	Change in foreign deferred tax rate			0.9			1.8			0
	Expiration of tax attributes			0.5			5.3			11.3
	Prior year true up			(0.7	)		—			—
	Tax credits			(3.0	)		—			—
	Warrant valuation			(4.1	)		—			—
	Effective tax (benefit) rate			0	%		0	%		0	%
	We did not have any unrecognized tax benefits at December 31, 2013. 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 2013 or accrued as a liability in our consolidated balance sheets at December 31, 2013. 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.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Accumulated Other Comprehensive Income	'
	Note 19. Accumulated Other Comprehensive Income
	The following table sets forth the changes in accumulated other comprehensive loss by component for the year ended December 31, 2013:
		Unrealized			Foreign Currency		Total
		Gain (loss)			Translation
		on Other
		Available-for-Sale
		Securities
	Beginning balance	$	(1,356	)	$	194,533	$	193,177
	Other comprehensive income before reclassifications		1,356			57,568		58,924
	Amounts reclassified from accumulated other comprehensive loss		—			—		—
	Net current-period other comprehensive income (loss)		1,356			57,568		58,924
	Ending balance	$	—		$	252,101	$	252,101

Quarterly_Financial_Data

Quarterly Financial Data	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Quarterly Financial Data	'
	QUARTERLY FINANCIAL DATA (unaudited)
			2013 Quarter Ended
			December 31		September 30		June 30		March 31
			(In thousands, except per share amounts)
	Total revenue		$	313	$	325	$	282	$	284
	Cost of Sales			86		86		78		67
	Operating expenses			9,697		6,895		6,425		6,475
	Other income (expense), net(1)			2,508		-536		353		-159
	Net loss			-6,962		-7,192		-5,869		-6,416
	Basic and diluted net loss per share		$	-0.13	$	-0.17	$	-0.15	$	(0.17)
			2012 Quarter Ended
			December 31		September 30		June 30		March 31
			(In thousands, except per share amounts)
	Total revenue		$	211	$	264	$	249	$	644
	Cost of Sales			55		72		64		72
	Operating expenses			6,949		5,269		5,534		5,898
	Other income (expense), net(1)			4,034		-11,260		6,183		-4,903
	Net income (loss)			-2,758		-16,337		833		-10,229
	Basic and diluted net income (loss) per share		$	-0.07	$	-0.54	$	0.03	$	(0.45)
	-1	Other expense, net, for 2013 and 2012, includes the change in fair value of our warrant liability — see Note 13.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Nature of Business	'
	Nature of Business
	StemCells, Inc., a Delaware corporation, is a biopharmaceutical company that operates in one segment, the research, development, and commercialization of 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 $388 million at December 31, 2013. 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, and Stem Cell Sciences (UK) Ltd. All significant intercompany accounts and transactions have been eliminated.
Use of Estimates	'
	Use of Estimates
	The preparation of financial statements in conformity with 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
		•		the fair value of intangible assets acquired (see Note 5, “Goodwill and Other Intangible Assets”).
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. Our marketable debt and equity securities are accounted for as available-for-sale. Management determines the appropriate classification of its investments in marketable debt and equity securities at the time of purchase and reevaluates the available-for-sale designations as of each balance sheet date. These securities are carried at fair value (see Note 2, “Financial Instruments,” below), with the unrealized gains and losses reported as a component of stockholders’ equity. The cost of securities sold is based upon the specific identification method.
	If the estimated fair value of a security is below its carrying value, we evaluate whether we have the intent and ability to retain our investment for a period of time sufficient to allow for any anticipated recovery to the cost of the investment, and whether evidence indicating that the cost of the investment is recoverable within a reasonable period of time outweighs evidence to the contrary. Other-than-temporary declines in estimated fair value of all marketable securities are charged to “Other income (expense), net.”
	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.
Estimated Fair Value of Financial Instruments	'
	Estimated Fair Value of Financial Instruments
	The estimated fair values of cash and cash equivalents, receivables, accounts payable, and the current portion of the bonds payable approximates their carrying values due to the short maturities of these instruments. The long-term portion of the bonds payable approximates its carrying value as the interest rate for the bond series approximates our current borrowing rate.
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.
Business Combinations	'
	Business Combinations
	The operating results of acquired companies or operations are included in our consolidated financial statements starting on the date of acquisition. Goodwill is recorded at the time of an acquisition and is calculated as the difference between the aggregate consideration paid for an acquisition and the fair value of the net tangible and intangible assets acquired. Accounting for acquisitions requires extensive use of accounting estimates and judgments to allocate the purchase price to the fair value of the net tangible and intangible assets acquired, including in-process research and development (IPR&D).
Goodwill and Other Intangible Assets (Patent and License Costs)	'
	Goodwill and Other Intangible Assets (Patent and License Costs)
	Goodwill of approximately $2,139,000 at December 31, 2013, relates to the acquisition of SCS operations. Goodwill and intangible assets deemed to have indefinite lives are not amortized but are subject to annual impairment tests. If the assumptions and estimates used to allocate the purchase price are not correct, or if business conditions change, purchase price adjustments or future asset impairment charges could be required. We test goodwill for impairment on an annual basis or more frequently if we believe indicators of impairment exist. Impairment evaluations involve management estimates of asset useful lives and future cash flows. Significant management judgment is required in the forecasts of future operating results that are used in the evaluations, and it is possible, even likely, that the plans and estimates used may be incorrect. If our actual results, or the plans and estimates used in future impairment analysis are lower than the original estimates used to assess the recoverability of these assets, we could incur additional impairment charges in a future period. We completed our annual impairment testing during the fourth quarter of 2013, and determined that there was no impairment of goodwill.
	Other intangible assets, net were approximately $1,836,000 at December 31, 2013. Intangible assets with finite useful lives are amortized generally on a straight-line basis over the periods benefited. Intangible assets are 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.
	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 2011 and 2013.
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. As part of our December 2011 financing, we issued Series A Warrants with a five year term to purchase 8,000,000 shares at $1.40 per share and Series B Warrants with a ninety trading day term to purchase 8,000,000 units at $1.25 per unit. Each unit underlying the Series B Warrants consisted of one share of our common stock and one Series A Warrant. In the first and second quarter of 2012, an aggregate of 2,700,000 Series B Warrants were exercised. For the exercise of these warrants, we issued 2,700,000 shares of our common stock and 2,700,000 Series A Warrants. The remaining 5,300,000 Series B Warrants expired unexercised by their terms on May 2, 2012. As terms of the warrants issued in 2008 and 2009, as well as the Series A and Series B Warrants, do not meet the specific conditions for equity classification, we are required to classify the fair value of these warrants as a liability, with subsequent changes in fair value to be recorded as income (loss) due to change in fair value of warrant liability. The fair value of the warrants issued in the 2008 and 2009 financings is determined using the Black-Scholes-Merton (Black-Scholes) option pricing model and the fair value of the Series A and Series B Warrants is determined using a Monte Carlo simulation model (see Note 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, 2013, was approximately $5,542,000.
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. Product sales are presented net of any sales or value-added taxes.
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. We reported as a long-term liability on our balance sheet, a net deferred tax liability of approximately $118,000 that is related to an indefinite-lived intangible acquired as part of the SCS operations.
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:
			2013			2012			2011
	Net loss		$	(26,439,159	)	$	(28,491,153	)	$	(21,328,536	)
	Weighted average shares outstanding used to compute basic and diluted net loss per share			43,422,001			28,824,417			14,187,885
	Basic and diluted net loss per share		$	(0.61	)	$	(0.99	)	$	(1.50	)
	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:
			2013			2012			2011
	Outstanding options			428,258			447,359			875,498
	Restricted stock units			3,326,282			1,534,200			357,541
	Outstanding warrants			16,267,659			9,935,912			17,434,483
	Total			20,022,199			11,917,471			18,667,522
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:
			2013			2012
	Net unrealized gain (loss) on marketable securities		$	—		$	(1,356	)
	Unrealized gain on foreign currency translation			252,101			194,533
	Accumulated other comprehensive income		$	252,101		$	193,177
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	In July 2013, the Financial Accounting Standards Board (FASB) issued ASU 2013-11 “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists”, an update to Topic 740, Income Taxes. This Update applies to all entities that have unrecognized tax benefits when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists at the reporting date. The amendments in this Update are expected to reduce diversity in practice by providing guidance on the presentation of unrecognized tax benefits and to better reflect the manner in which an entity would settle at the reporting date any additional income taxes that would result from the disallowance of a tax position when net operating loss carryforwards, similar tax losses, or tax credit carryforwards exist. This update is effective for annual and interim reporting periods for fiscal years beginning after December 15, 2013. The adoption of the amended standard is not expected to have a material impact on our consolidated financial statements.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Estimated Useful Lives of Assets	'
	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
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:
		2013			2012			2011
	Net loss	$	(26,439,159	)	$	(28,491,153	)	$	(21,328,536	)
	Weighted average shares outstanding used to compute basic and diluted net loss per share		43,422,001			28,824,417			14,187,885
	Basic and diluted net loss per share	$	(0.61	)	$	(0.99	)	$	(1.50	)
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:
		2013			2012			2011
	Outstanding options		428,258			447,359			875,498
	Restricted stock units		3,326,282			1,534,200			357,541
	Outstanding warrants		16,267,659			9,935,912			17,434,483
	Total		20,022,199			11,917,471			18,667,522
Summary of Components of Accumulated OCI	'
	The components of our accumulated OCI, as of December 31 of each year shown, are as follows:
		2013			2012
	Net unrealized gain (loss) on marketable securities	$	—		$	(1,356	)
	Unrealized gain on foreign currency translation		252,101			194,533
	Accumulated other comprehensive income	$	252,101		$	193,177

Financial_Instruments_Tables

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2013
Investments Debt And Equity Securities [Abstract]	'
Available for Sale Securities Held in Investment Portfolio	'
	The following table summarizes the fair value of our cash, cash equivalents and available-for-sale securities held in our investment portfolio:
		Amortized		Gross		Gross			Fair Value
		Cost		Unrealized		Unrealized
				Gains		Losses
	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
	December 31, 2012
	Cash	$	254,267	$	—	$	—		$	254,267
	Cash equivalents (money market accounts)		8,217,259		—		(252	)		8,217,007
	Marketable debt securities, current		13,901,782		—		(1,104	)		13,900,678
	Total cash, cash equivalents, and marketable securities	$	22,373,308	$	—	$	(1,356	)	$	22,371,952

Fair_Value_Measurement_Tables

Fair Value Measurement (Tables)	12 Months Ended
	Dec. 31, 2013
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:
		Fair Value Measurement						Unobservable
		at Reporting Date Using						Inputs
		Quoted Prices			Significant Other			(Level 3)			As of
		in Active Markets for			Observable Inputs						December 31,
		Identical Assets			(Level 2)						2013
		(Level 1)
	Financial assets
	Cash equivalents:
	Money market funds	$	821,335		$	—		$	—		$	821,335
	U.S. Treasury debt obligations		28,408,808			—			—			28,408,808
	Total financial assets	$	29,230,143		$	—		$	—		$	29,230,143
	Financial liabilities
	Bond obligation	$	—		$	125,000		$	—		$	125,000
	Loan payable net of discounts		—			—			12,909,244			12,909,244
	Warrant liabilities		—			—			5,541,810			5,541,810
	Total financial liabilities	$	—		$	125,000		$	18,451,054		$	18,576,054
Roll Forward for Financial Assets and Liabilities Measured at Fair Value Using Significant Other Observable Inputs (Level 2)	'
	Level 2 Reconciliation
	The following table presents a roll forward for financial assets and liabilities measured at fair value using significant other observable inputs (Level 2) for 2013.
		Level 2			Net transfers (to)			Change			Settled			Level 2
		Beginning			from			included in			$			Ending
		Balance 12/31/12			Level 1			earnings						Balance 12/31/13
		$			$			$						$
	Marketable debt securities		13,900,678			(13,900,678	)		—			—			—
	Bond obligation		331,250			—			—			(206,250	)		125,000
	Warrant liabilities		107,968			—			(107,968	)		—			—
Roll Forward for Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3)	'
	Level 3 Reconciliation
	The following table presents a roll forward for liabilities measured at fair value using significant unobservable inputs (Level 3) for 2013.
		Warrant
		Liabilities
	Balance at December 31, 2012	$	9,157,397
	Less fair value of warrants exercised		(470,303	)
	Add change in fair value of warrants		(3,145,285	)
	Balance at December 31, 2013	$	5,541,809
		Loan
		Payable
	Balance at December 31, 2012	$	—
	Add loan proceeds		13,820,264
	Less discount		(487,576	)
	Initial carrying value	$	13,332,688
	Less repayments of principal		(620,215	)
	Add accretion of discount		196,771
	Balance at December 31, 2013	$	12,909,244
	Current portion	$	3,664,370
	Non-current portion		9,244,874
	Balance at December 31, 2013	$	12,909,244

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2013
Property Plant And Equipment [Abstract]	'
Summary of Property, Plant and Equipment Balances	'
	Property, plant and equipment balances at December 31 are summarized below:
		2013			2012
	Building and improvements	$	6,751,393		$	3,441,192
	Machinery and equipment		7,837,140			6,671,866
	Furniture and fixtures		602,599			595,619
			15,191,132			10,708,677
	Less accumulated depreciation and amortization		(9,886,448	)		(9,333,348	)
	Property, plant and equipment, net	$	5,304,684		$	1,375,329

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'
Purchase Price Allocated	'
	At April 1, 2009, the purchase price has been 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 2013:
	Balance as of December 31, 2012	$	1,983,426
	Net deferred tax liability related to indefinite lived IPR&D		117,815
	Foreign currency translation		38,053
	Balance as of December 31, 2013	$	2,139,294
Components of Other Intangible Assets	'
	The components of our other intangible assets at December 31, 2013 are summarized below:
	Other Intangible	Cost		Acquisition		Impairment			Accumulated			Foreign Currency		Net Carrying		Weighted-
	Asset Class								Amortization			Translation		Amount		Average
																Amortization
																Period
	Customer relationships and developed technology	$	1,310,000	$	—	$	—		$	(876,535	)	$	156,966	$	590,431		8.0 years
	In-process research and development		1,340,000		—		(654,961	)		(270,687	)		146,672		561,024		Indefinite
	Trade name		310,000		—		—			(107,944	)		41,748		243,804		15.0 years
	Patents		979,612		264,000		—			(803,154	)		—		440,458		17.0 years
	Total other intangible assets	$	3,939,612	$	264,000	$	(654,961	)	$	(2,058,320	)	$	345,386	$	1,835,717		12.7 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:
	2014	$	300,434
	2015	$	242,588
	2016	$	215,639
	2017	$	195,066
	2018	$	80,851

Other_Assets_Tables

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2013
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:
		2013		2012
	Prepaid royalties	$	—	$	614,488
	Security deposit (buildings and equipment lease)		413,717		332,813
	Total other non-current assets	$	413,717	$	947,301

Accounts_Payable_Tables

Accounts Payable (Tables)	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Summary of Accounts Payable	'
	Accounts payable at December 31 are summarized below:
		2013		2012
	External services	$	863,030	$	678,813
	Supplies		263,866		216,900
	Other		25,007		103,652
	Total accounts payable	$	1,151,903	$	999,365

Accrued_Expenses_and_Other_Cur1

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Summary of Accrued Expenses	'
	Accrued expenses at December 31 are summarized below:
		2013		2012
	External services	$	1,191,048	$	900,580
	Employee compensation		2,655,242		1,577,322
	Other		221,626		229,539
	Total accrued expenses and other current liabilities	$	4,067,916	$	2,707,441

Other_LongTerm_Liabilities_Tab

Other Long-Term Liabilities (Tables)	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Schedule of Other Long-Term Liabilities	'
		2013		2012
	Accrued interest on loan payable	$	497,134	$	—
	Employee compensation		186,439		216,439
	Net deferred tax liability		117,815		—
	Total accrued expenses and other current liabilities	$	801,388	$	216,439

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock-Based Compensation Expense	'
	Our stock-based compensation expense for the last three fiscal years was as follows:
			2013			2012			2011
	Research and development expense		$	1,219,308		$	1,280,298		$	1,680,431
	General and administrative expense			1,389,362			1,597,836			1,580,506
	Total stock-based compensation expense and effect on net loss		$	2,608,670		$	2,878,134		$	3,260,937
Schedule of Fair Value Option Award, Assumptions	'
	The weighted-average assumptions used for the last three fiscal years are as follows:
			2013			2012			2011
	Expected term (years)(1)			5.1			6.4			7.4
	Risk-free interest rate(2)			1.2	%		1.4	%		2.7	%
	Expected volatility(3)			89.3	%		78.4	%		79.7	%
	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, 2010			1,098,241		$	20.2			6.1		$	398,219
	Granted			3,750		$	7.3
	Exercised			(1,692	)	$	1.41					$	11,293
	Cancelled (forfeited and expired)			(224,801	)	$	20.22
	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		$	—
	Exercisable at December 31, 2013			409,792		$	20.42			4.2		$	—
	Vested and expected to vest(2)			426,027		$	20.02			4.3		$	—
	-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, 2012			64,503		$	8.67
	Granted			—			—
	Vested			(45,564	)	$	8.91
	Cancelled			(473	)	$	7.82
	Unvested options at December 31, 2013			18,466		$	8.11
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, 2013:
	Options Outstanding at December 31, 2013
	Range of		Number			Weighted Average			Weighted Average			Aggregate Intrinsic
	Exercise Prices		Outstanding			Remaining			Exercise			Value at December 31,
						Term (Yrs.)			Price			2013
	Less than $10.00			4,050			7.3		$	7.42		$	—
	$10.00 - $19.99			250,949			5.3		$	12.65			—
	$20.00 - $29.99			117,459			3.1		$	23.22			—
	$30.00 - $39.99			19,800			1.9		$	36.46			—
	$40.00 - $49.99			5,500			1.7		$	46.51			—
	$50.00 - $59.99			30,500			1.7		$	53.94			—
				428,258			4.3		$	19.97		$	—
	Vested Options Outstanding at December 31, 2013
	Range of Exercise Prices		Number			Weighted Average
			Outstanding			Exercise Price
	Less than $10.00			2,677		$	7.45
	$10.00 - $19.99			233,856		$	12.81
	$20.00 - $29.99			117,459		$	23.22
	$30.00 - $39.99			19,800		$	36.46
	$40.00 - $49.99			5,500		$	46.51
	$50.00 - $59.99			30,500		$	53.94
				409,792		$	20.42
Summary of Restricted Stock Unit Activity	'
	A summary of our restricted stock unit activity for the year ended December 31, 2013 is as follows:
			Number of			Weighted Average
			RSUs			Grant Date Fair
						Value
	Outstanding at January 1, 2013			1,534,200		$	2.1
	Granted(1)			2,421,965		$	1.8
	Vested and exercised			(565,883	)	$	3.37
	Cancelled			(64,000	)	$	1.61
	Outstanding at December 31, 2013			3,326,282		$	1.68
	-1	11,765 of these restricted stock units vested on the date of grant. 55,000 of these restricted stock units vest and convert into shares of our common stock after one year from the date of grant. 2,355,200 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.
Summary of Changes in Outstanding SARs	'
	The following is a summary of the changes in our outstanding SARs for the last three fiscal years:
			2013						2012					2011
			Number			Weighted			Number			Weighted		Number			Weighted
						Average						Average					Average
						Exercise						Exercise					Exercise
						Price						Price					Price
	Outstanding at January 1,			110,593		$	20			115,187		$	20		135,409		$	20
	Granted			—			—			—			—		—			—
	Exercised			—			—			—			—		—			—
	Forfeited			—						(4,594	)				(20,222	)
	Outstanding at December 31,			110,593		$	20			110,593		$	20		115,187		$	20
	Exercisable at December 31,			110,593		$	20			110,593		$	20		115,187		$	20

WindDown_and_Exit_Costs_Tables

Wind-Down and Exit Costs (Tables)	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Components of Wind-Down Reserve	'
	The components of our wind-down reserve at December 31 are as follows:
		2013			2012
	Accrued wind-down reserve at beginning of period	$	854,000		$	1,683,000
	Less actual expenses recorded against estimated reserve during the period		(916,000	)		(1,185,000	)
	Additional expense recorded to revise estimated reserve		62,000			356,000
	Revised reserve at period-end		—			854,000
	Add deferred rent at period end		—			249,000
	Total accrued wind-down expenses at period-end (current)	$	—		$	1,103,000

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
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:
			2013			2012			2011
	Rent expense		$	2,612,899		$	2,932,104		$	4,193,433
	Sublease income			(53,726	)		(411,885	)		(424,847	)
	Rent expense, net		$	2,559,173		$	2,520,219		$	3,768,586
Future Minimum Payments Under All Leases and Bond Payable	'
	Future minimum payments under all leases, bond payable and loan payable at December 31, 2013 are as follows:
			Bonds			Loan(1)			Capital			Operating
			Payable			Payable			Leases			Leases
	2014		$	136,852		$	4,322,035		$	24,284		$	1,917,423
	2015			—			4,322,035			21,591			1,912,217
	2016			—			1,440,678			9,454			1,968,459
	2017			—			—			—			2,014,706
	2018			—			—			—			2,061,260
	Thereafter			—			—			—			8,196,910
	Total minimum lease payments			136,852			10,084,748			55,329		$	18,070,975
	Less amounts representing interest			11,852			704,963			4,591
	Principal amounts of bond payable, loan payable and capital lease obligations			125,000			9,379,785			50,738
	Less current maturities			125,000			3,857,971			20,936
	Bond payable, loan payable and capital lease obligations, less current maturities		$	—		$	5,521,814		$	29,802
	-1	Approximately $3.8 million received as initial disbursement of the loan provided under the CIRM Loan Agreement is not included. In April 2013, we entered into an agreement with CIRM under which CIRM will provide up to approximately $19.3 million to help fund preclinical development and IND-enabling activities of our HuCNS-SC cells for Alzheimer’s disease. The funding is in the form of a forgivable loan, in accordance with mutually agreed upon terms and conditions and CIRM regulations, and is expected to be disbursed periodically by CIRM over the four-year project period subject to a number of preconditions, including the achievement of certain progress milestones and compliance with certain financial covenants. The loan is unsecured and the term of the loan is ten years and may be extended under certain circumstances.

Loan_Payable_Tables

Loan Payable (Tables)	12 Months Ended
	Dec. 31, 2013
Assumptions Used for Black-Scholes Option Pricing Model	'
	The assumptions used for the Black-Scholes option pricing model are as follows:
		To Calculate
		Fair Value of
		Warrant Liability at
		December 31,
		2013			2012
	Expected life (years)		0.4			1.4
	Risk-free interest rate		0.1	%		0.2	%
	Expected volatility		46.1	%		108.2	%
	Expected dividend yield		0	%		0	%
		At December 31,			At December 31,			Change in Fair Value
		2013			2012			of Warrant Liability
								in Year 2013
	Fair value of warrant liability	$	—		$	44,628		$	(44,628	)
	The assumptions used for the Black-Scholes option pricing model are as follows:
		To Calculate
		Fair Value of
		Warrant Liability at
		December 31,			December 31,
		2013			2012
	Expected life (years)		1.3			2.3
	Risk-free interest rate		0.2	%		0.3	%
	Expected volatility		48.2	%		94.5	%
	Expected dividend yield		0	%		0	%
		At December 31,			At December 31,			Change in Fair Value
		2013			2012			of Warrant Liability
								in Year 2013
	Fair value of warrant liability	$	—		$	63,340		$	(63,340	)
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:
		Silicon Valley			CIRM Loan			Total
		Bank Loan
	Loan proceeds	$	10,000,000		$	3,820,264		$	13,820,264
	Cash discount		(100,000	)					(100,000	)
	Fair value of warrants issued		(387,576	)		—			(387,576	)
	Initial carrying value		9,512,424			3,820,264			13,332,688
	Repayment of principal		(620,215	)		—			(620,215	)
	Accretion of discount		196,771			—			196,771
	Carrying value of loan payable at 12/31/2013 (current and non-current)	$	9,088,980		$	3,820,264		$	12,909,244
	Carrying value of loan payable, current portion	$	3,664,370		$	—		$	3,664,370
	Carrying value of loan payable, non-current portion		5,424,610			3,820,264			9,244,874
	Total loan payable at 12/31/2013	$	9,088,980		$	3,820,264		$	12,909,244
Silicon Valley Bank Loan Agreement Warrant [Member]	'
Assumptions Used for Black-Scholes Option Pricing Model	'
	We estimated the fair value of the warrant to be approximately $388,000 using the Black-Scholes option pricing model with the following assumptions:
	Expected life (years)		10
	Risk-free interest rate		1.9	%
	Expected volatility		88.1	%
	Expected dividend yield		0	%

Warrant_Liability_Tables

Warrant Liability (Tables)	12 Months Ended
	Dec. 31, 2013
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, 2013 are as follows:
	Risk-free interest rate per year		0.8	%
	Expected volatility per year		85.2	%
	Expected dividend yield		0	%
	Expected life (years)		3
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 2013:
		Series A
		Number of			Fair value $
		Warrants
	Balance at December 31, 2012		8,501,429		$	9,157,397
	Less exercised		(384,534	)		(470,303	)
	Changes in fair value		—			(3,145,285	)
	Balance at December 31, 2013		8,116,895		$	5,541,809
Summary of Warrant Liability	'
	The following table is a summary of our warrant liability as of December 31, 2013:
	Warrants	Number Outstanding			Exercise Price ($)			Fair value
					per share
	Warrants issued in 2008		1,034,483			23		$	—
	Warrants issued in 2009		400,000			15			—
	Series A Warrants		8,116,895			1.4			5,541,809
	Total		9,551,378					$	5,541,809

Common_Stock_Tables

Common Stock (Tables)	12 Months Ended
	Dec. 31, 2013
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, 2013:
	Shares reserved for share based compensation	12,308,148
	Shares reserved for warrants related to financing transactions	16,267,659
	Total	28,575,807

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
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,
		2013			2012
	United States	$	26,080,000		$	28,356,000
	Foreign		359,000			133,000
	Total loss before income taxes	$	26,439,000		$	28,489,000
Components of Deferred Tax Assets and Liabilities	'
	Significant components of our deferred tax assets and liabilities at December 31 are as follows:
		2013			2012
	Deferred tax assets:
	Capitalized research and development costs	$	59,426,000		$	53,824,000
	Net operating losses		56,906,000			53,687,000
	Research and development credits		8,931,000			7,777,000
	Accrued wind down cost		—			292,000
	Stock-based compensation		1,063,000			853,000
	Capital loss carryover		541,000			544,000
	Fixed assets		452,000			430,000
	Other		1,289,000			1,002,000
			128,608,000			118,409,000
	Valuation allowance		(128,315,000	)		(118,045,000	)
	Total deferred tax assets	$	293,000		$	364,000
	Deferred tax liability:
	Intangible assets		(293,000	)		(364,000	)
	Total deferred tax liability	$	(293,000	)	$	(364,000	)
	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:
		2013			2012			2011
	Statutory federal income tax (benefit) rate		(34	)%		(34	)%		(34	)%
	State income tax (benefit) rate		—			(3.3	)		(3.4	)
	Increase resulting from:
	Expenses not deductible for taxes		0.5			8.8			(6.7	)
	Increase in valuation allowance		38.8			3.7			32.8
	Change in state deferred tax rate		1.1			17.7			0
	Change in foreign deferred tax rate		0.9			1.8			0
	Expiration of tax attributes		0.5			5.3			11.3
	Prior year true up		(0.7	)		—			—
	Tax credits		(3.0	)		—			—
	Warrant valuation		(4.1	)		—			—
	Effective tax (benefit) rate		0	%		0	%		0	%

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2013
Text Block [Abstract]	'
Summary of Changes in Accumulated Other Comprehensive Loss by Component	'
	The following table sets forth the changes in accumulated other comprehensive loss by component for the year ended December 31, 2013:
		Unrealized			Foreign Currency		Total
		Gain (loss)			Translation
		on Other
		Available-for-Sale
		Securities
	Beginning balance	$	(1,356	)	$	194,533	$	193,177
	Other comprehensive income before reclassifications		1,356			57,568		58,924
	Amounts reclassified from accumulated other comprehensive loss		—			—		—
	Net current-period other comprehensive income (loss)		1,356			57,568		58,924
	Ending balance	$	—		$	252,101	$	252,101

Quarterly_Financial_Data_Table

Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Summary of Quarterly Financial Data	'
			2013 Quarter Ended
			December 31		September 30		June 30		March 31
			(In thousands, except per share amounts)
	Total revenue		$	313	$	325	$	282	$	284
	Cost of Sales			86		86		78		67
	Operating expenses			9,697		6,895		6,425		6,475
	Other income (expense), net(1)			2,508		-536		353		-159
	Net loss			-6,962		-7,192		-5,869		-6,416
	Basic and diluted net loss per share		$	-0.13	$	-0.17	$	-0.15	$	(0.17)
			2012 Quarter Ended
			December 31		September 30		June 30		March 31
			(In thousands, except per share amounts)
	Total revenue		$	211	$	264	$	249	$	644
	Cost of Sales			55		72		64		72
	Operating expenses			6,949		5,269		5,534		5,898
	Other income (expense), net(1)			4,034		-11,260		6,183		-4,903
	Net income (loss)			-2,758		-16,337		833		-10,229
	Basic and diluted net income (loss) per share		$	-0.07	$	-0.54	$	0.03	$	(0.45)
	-1	Other expense, net, for 2013 and 2012, includes the change in fair value of our warrant liability — see Note 13.

Summary_of_Significant_Account3

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

1 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

1 Months Ended

Oct. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Oct. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2011

Dec. 31, 2011

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Nov. 30, 2008

Nov. 30, 2008

Dec. 31, 2013

Dec. 31, 2013

Nov. 30, 2009

Nov. 30, 2009

Segment

Outstanding warrants [Member]

Common Stock [Member]

Marketable debt securities, current [Member]

Marketable securities, non-current [Member]

Indefinite-lived intangible acquired [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

November 2008 Financing [Member]

November 2008 Financing [Member]

November 2008 Financing [Member]

November 2008 Financing [Member]

November 2009 Financing [Member]

November 2009 Financing [Member]

November 2009 Financing [Member]

November 2009 Financing [Member]

Minimum [Member]

Maximum [Member]

Common Stock [Member]

Common Stock [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series B Warrants [Member]

Series B Warrants [Member]

Outstanding warrants [Member]

Common Stock [Member]

Outstanding warrants [Member]

Outstanding warrants [Member]

Common Stock [Member]

Outstanding warrants [Member]

Common Stock [Member]

Class of Warrant or Right [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of segments

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Accumulated deficit

'

($387,530,334)

($361,091,175)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maturity period for money market and highly liquid investments

'

'90 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Investments with maturities

'

'

'

'

'

'

'365 days or less

'Greater than 365 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Goodwill

'

2,139,294

1,983,426

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Impairment of goodwill

'

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Intangible assets with finite useful lives

'

1,836,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Intangible asset impaired and wrote off carrying value of the asset

'

'

'

654,961

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Value of patent

'

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of certain lab equipment

'

0

28,000

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrant component

'

'

'

'

'

0.5

'

'

'

1

'

'

'

1

'

'

'

'

'

0.75

'

'

'

0.4

'

Number of securities callable by warrants

'

'

'

'

'

'

'

'

'

'

'

8,000,000

'

'

'

8,000,000

'

'

'

1,034,483

'

'

'

400,000

'

Exercise price of warrants

1.8

'

'

'

'

'

'

'

'

'

'

'

'

'

1.4

1.25

'

23

'

23

'

15

'

15

'

Term of warrant

'

'

'

'

'

'

'

'

'

'

'

'5 years

'

'

'

'90 days

'

'

'

'

'5 years

'

'

'

'5 years

Common stock per unit

'

'

$1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrants issued per unit

'

'

$1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of warrants exercised

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,700,000

'

'

'

'

'

'

'

'

Number of shares issued upon Series B warrants exercise

12,845,500

'

'

'

'

'

'

'

'

384,534

2,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of warrants issued upon Series B warrants exercise

'

'

'

'

'

'

'

'

'

'

'

'

2,700,000

'

'

'

'

'

'

'

'

'

'

'

'

Number of warrants expired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,300,000

'

'

'

'

'

'

'

'

Fair value of derivative liability

'

'

'

'

5,541,809

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net deferred tax liability

'

$293,000

$364,000

'

'

'

'

'

$118,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Estimated Useful Lives of Assets (Detail)	12 Months Ended
	Dec. 31, 2013
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, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounting Policies [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Net loss	($6,962,000)	($7,192,000)	($5,869,000)	($6,416,000)	($2,758,000)	($16,337,000)	$833,000	($10,229,000)	($26,439,159)	($28,491,153)	($21,328,538)
Weighted average shares outstanding used to compute basic and diluted net loss per share	'	'	'	'	'	'	'	'	43,422,001	28,824,417	14,187,885
Basic and diluted net loss per share	($0.13)	($0.17)	($0.15)	($0.17)	($0.07)	($0.54)	$0.03	($0.45)	($0.61)	($0.99)	($1.50)

Summary_of_Significant_Account6

Summary of Significant Accounting Policies - Outstanding Options, Warrants and Restricted Stock Units (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Class of Stock [Line Items]	'	'	'
Outstanding options, warrants and restricted stock units	20,022,199	11,917,471	18,667,522
Options [Member]	'	'	'
Class of Stock [Line Items]	'	'	'
Outstanding options, warrants and restricted stock units	428,258	447,359	875,498
Restricted stock units [Member]	'	'	'
Class of Stock [Line Items]	'	'	'
Outstanding options, warrants and restricted stock units	3,326,282	1,534,200	357,541
Outstanding warrants [Member]	'	'	'
Class of Stock [Line Items]	'	'	'
Outstanding options, warrants and restricted stock units	16,267,659	9,935,912	17,434,483

Summary_of_Significant_Account7

Summary of Significant Accounting Policies - Summary of Components of Accumulated OCI (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Other Comprehensive Income Loss Net Of Tax Period Increase Decrease [Abstract]	'	'
Net unrealized gain (loss) on marketable securities	'	($1,356)
Unrealized gain on foreign currency translation	252,101	194,533
Accumulated other comprehensive income	$252,101	$193,177

Financial_Instruments_Availabl

Financial Instruments - Available for Sale Securities Held in Investment Portfolio (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	$30,585,424	$22,373,308
Gross Unrealized Gains	'	'
Gross Unrealized Losses	'	-1,356
Fair Value	30,585,424	22,371,952
Cash [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	1,355,281	254,267
Gross Unrealized Gains	'	'
Gross Unrealized Losses	'	'
Fair Value	1,355,281	254,267
Cash equivalents (money market accounts) [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	29,230,143	8,217,259
Gross Unrealized Gains	'	'
Gross Unrealized Losses	'	-252
Fair Value	29,230,143	8,217,007
Marketable debt securities, current [Member]	'	'
Schedule of Available-for-sale Securities [Line Items]	'	'
Amortized Cost	'	13,901,782
Gross Unrealized Gains	'	'
Gross Unrealized Losses	'	-1,104
Fair Value	'	$13,900,678

Financial_Instruments_Addition

Financial Instruments - Additional Information (Detail) (Subsidiaries [Member], USD $)	Dec. 31, 2013
Subsidiaries [Member]	'
Cash and Cash Equivalents [Line Items]	'
Cash	$146,000

Fair_Value_Measurement_Financi

Fair Value Measurement - Financial Assets and Liabilities Measured at Fair Value (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Outstanding warrants [Member]	'	'
Financial liabilities	'	'
Total financial liabilities	$5,541,809	'
Fair Value, Measurements [Member]	'	'
Financial assets	'	'
Total financial assets	29,230,143	'
Financial liabilities	'	'
Total financial liabilities	18,576,054	'
Fair Value, Measurements [Member] | Money market funds [Member] | Cash equivalents (money market accounts) [Member]	'	'
Financial assets	'	'
Total financial assets	821,335	'
Fair Value, Measurements [Member] | U.S. Treasury debt obligations [Member] | Cash equivalents (money market accounts) [Member]	'	'
Financial assets	'	'
Total financial assets	28,408,808	'
Fair Value, Measurements [Member] | Bond obligation [Member]	'	'
Financial liabilities	'	'
Total financial liabilities	125,000	'
Fair Value, Measurements [Member] | Loan Payable [Member]	'	'
Financial liabilities	'	'
Total financial liabilities	12,909,244	'
Fair Value, Measurements [Member] | Outstanding warrants [Member]	'	'
Financial liabilities	'	'
Total financial liabilities	5,541,810	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements [Member]	'	'
Financial assets	'	'
Total financial assets	29,230,143	'
Financial liabilities	'	'
Total financial liabilities	'	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements [Member] | Money market funds [Member] | Cash equivalents (money market accounts) [Member]	'	'
Financial assets	'	'
Total financial assets	821,335	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements [Member] | U.S. Treasury debt obligations [Member] | Cash equivalents (money market accounts) [Member]	'	'
Financial assets	'	'
Total financial assets	28,408,808	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements [Member] | Bond obligation [Member]	'	'
Financial liabilities	'	'
Total financial liabilities	'	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements [Member] | Loan Payable [Member]	'	'
Financial liabilities	'	'
Total financial liabilities	'	'
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value, Measurements [Member] | Outstanding warrants [Member]	'	'
Financial liabilities	'	'
Total financial liabilities	'	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements [Member]	'	'
Financial assets	'	'
Total financial assets	'	'
Financial liabilities	'	'
Total financial liabilities	125,000	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements [Member] | Money market funds [Member] | Cash equivalents (money market accounts) [Member]	'	'
Financial assets	'	'
Total financial assets	'	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements [Member] | U.S. Treasury debt obligations [Member] | Cash equivalents (money market accounts) [Member]	'	'
Financial assets	'	'
Total financial assets	'	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements [Member] | Bond obligation [Member]	'	'
Financial assets	'	'
Total financial assets	125,000	331,250
Financial liabilities	'	'
Total financial liabilities	125,000	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements [Member] | Loan Payable [Member]	'	'
Financial liabilities	'	'
Total financial liabilities	'	'
Significant Other Observable Inputs Level 2 [Member] | Fair Value, Measurements [Member] | Outstanding warrants [Member]	'	'
Financial assets	'	'
Total financial assets	'	107,968
Financial liabilities	'	'
Total financial liabilities	'	'
Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member]	'	'
Financial assets	'	'
Total financial assets	'	'
Financial liabilities	'	'
Total financial liabilities	18,451,054	'
Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member] | Money market funds [Member] | Cash equivalents (money market accounts) [Member]	'	'
Financial assets	'	'
Total financial assets	'	'
Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member] | U.S. Treasury debt obligations [Member] | Cash equivalents (money market accounts) [Member]	'	'
Financial assets	'	'
Total financial assets	'	'
Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member] | Bond obligation [Member]	'	'
Financial liabilities	'	'
Total financial liabilities	'	'
Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member] | Loan Payable [Member]	'	'
Financial liabilities	'	'
Total financial liabilities	12,909,244	'
Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements [Member] | Outstanding warrants [Member]	'	'
Financial liabilities	'	'
Total financial liabilities	$5,541,810	'

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 $)	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
		Significant Other Observable Inputs Level 2 [Member]	Significant Other Observable Inputs Level 2 [Member]	Significant Other Observable Inputs Level 2 [Member]	Significant Other Observable Inputs Level 2 [Member]	Significant Other Observable Inputs Level 2 [Member]
			Bond obligation [Member]	Outstanding warrants [Member]	Marketable securities [Member]	Marketable securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]	'	'	'	'	'	'
Marketable debt securities, Beginning Balance	$29,230,143	'	$331,250	$107,968	'	$13,900,678
Fair Value Measurement With Unobservable inputs reconciliation recurring basis asset transfers into level 1	'	'	'	'	-13,900,678	'
Financial liabilities change included in earning fair value disclosure	'	'	'	-107,968	'	'
Financial liabilities change settled in earning fair value disclosure	'	'	-206,250	'	'	'
Marketable debt securities, Ending Balance	$29,230,143	'	$125,000	'	'	$13,900,678

Fair_Value_Measurement_Roll_Fo1

Fair Value Measurement - Roll Forward for Liabilities Measured at Fair Value Using Significant Unobservable Inputs (Level 3) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'
Add loan proceeds	$13,820,264
Initial carrying value	13,332,688
Less repayments of principal	-620,215
Add accretion of discount	196,771
Outstanding warrants [Member]	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'
Balance at December 31, 2012	9,157,397
Less fair value of warrants exercise	-470,303
Add change in fair value of warrants	-3,145,285
Balance at December 31, 2013	5,541,809
Loan Payable [Member]	'
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]	'
Add loan proceeds	13,820,264
Less discount	-487,576
Initial carrying value	13,332,688
Less repayments of principal	-620,215
Add accretion of discount	196,771
Balance at December 31, 2013	12,909,244
Current portion	3,664,370
Non-current portion	$9,244,874

Property_Plant_and_Equipment_S

Property, Plant and Equipment - Summary of Property, Plant and Equipment Balances (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]	'	'
Property, Plant and Equipment, Gross, Total	$15,191,132	$10,708,677
Less accumulated depreciation and amortization	-9,886,448	-9,333,348
Property, plant and equipment, net	5,304,684	1,375,329
Building and improvements [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, Plant and Equipment, Gross, Total	6,751,393	3,441,192
Machinery and equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, Plant and Equipment, Gross, Total	7,837,140	6,671,866
Furniture and fixtures [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, Plant and Equipment, Gross, Total	$602,599	$595,619

Property_Plant_and_Equipment_A

Property, Plant and Equipment - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property Plant And Equipment [Abstract]	'	'	'
Depreciation expense	$789,000	$728,000	$842,000

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended				0 Months Ended	1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2009	Apr. 30, 2009	Mar. 31, 2009	Dec. 31, 2013	Mar. 31, 2009	Dec. 31, 2013
					Trade name [Member]	Trade name [Member]	Trade name [Member]	In-process research and development [Member]	In-process research and development [Member]
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'	'	'	'	'	'	'
Aggregate purchase price	'	'	'	$5,135,000	'	'	'	'	'
Minimum expiration year of intangible assets	'	'	'	'	'	'	'	'	'2027
Impairment amount of intangible asset	'	'	655,000	'	'	'	'	'	'
Useful life	'12 years 8 months 12 days	'	'	'	'15 years	'15 years	'15 years	'	'
Amortization expense	$269,000	$264,000	$366,000	'	'	'	'	'	'

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible Assets - Purchase Price Allocated (Detail) (USD $)	0 Months Ended	1 Months Ended	12 Months Ended
	Apr. 30, 2009	Mar. 31, 2009	Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'
Weighted Average Amortization Period	'	'	'12 years 8 months 12 days
Net tangible assets	'	$36,000	'
Total	'	5,135,000	'
Customer relationships and developed technology [Member]	'	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'
Weighted Average Amortization Period	'	'	'8 years
Allocated Purchase Price	'	1,310,000	'
Customer relationships and developed technology [Member] | Minimum [Member]	'	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'
Weighted Average Amortization Period	'	'6 years	'
Customer relationships and developed technology [Member] | Maximum [Member]	'	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'
Weighted Average Amortization Period	'	'9 years	'
In-process research and development [Member]	'	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'
Weighted Average Amortization Period	'	'	'
Allocated Purchase Price	'	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	'
Goodwill [Member]	'	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'
Weighted Average Amortization Period	'	'	'
Goodwill	'	$2,139,000	'

Goodwill_and_Other_Intangible_4

Goodwill and Other Intangible Assets - Changes in Goodwill (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Balance as of December 31, 2012	$1,983,426	'
Net deferred tax liability	293,000	364,000
Foreign currency translation	38,053	'
Balance as of December 31, 2013	2,139,294	'
In-process research and development [Member]	'	'
Acquired Finite-Lived Intangible Assets [Line Items]	'	'
Net deferred tax liability	$117,815	'

Goodwill_and_Other_Intangible_5

Goodwill and Other Intangible Assets - Components of Other Intangible Assets (Detail) (USD $)	12 Months Ended		12 Months Ended	1 Months Ended	12 Months Ended	0 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Mar. 31, 2009	Dec. 31, 2013	Apr. 30, 2009	Mar. 31, 2009	Dec. 31, 2013	Dec. 31, 2013
			Customer relationships and developed technology [Member]	In-process research and development [Member]	In-process research and development [Member]	Trade name [Member]	Trade name [Member]	Trade name [Member]	Patents [Member]
Acquired Finite-Lived Intangible Assets [Line Items]	'	'	'	'	'	'	'	'	'
Cost	$3,939,612	'	$1,310,000	'	$1,340,000	'	'	$310,000	$979,612
Acquisition	264,000	'	'	'	'	'	'	'	264,000
Impairment	-654,961	'	'	'	-654,961	'	'	'	'
Accumulated Amortization	-2,058,320	'	-876,535	'	-270,687	'	'	-107,944	-803,154
Foreign Currency Translation	345,386	'	156,966	'	146,672	'	'	41,748	'
Net Carrying Amount	$1,835,717	$1,822,904	$590,431	'	$561,024	'	'	$243,804	$440,458
Weighted- Average Amortization Period	'12 years 8 months 12 days	'	'8 years	'	'	'15 years	'15 years	'15 years	'17 years

Goodwill_and_Other_Intangible_6

Goodwill and Other Intangible Assets - Expected Future Annual Amortization Expense (Detail) (USD $)	Dec. 31, 2013
Goodwill And Intangible Assets Disclosure [Abstract]	'
2014	$300,434
2015	242,588
2016	215,639
2017	195,066
2018	$80,851

Other_Assets_Summary_of_Other_

Other Assets - Summary of Other Assets, Non-Current (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Summary Other assets	'	'
Prepaid royalties	'	$614,488
Security deposit (buildings and equipment lease)	413,717	332,813
Total other non-current assets	$413,717	$947,301

Accounts_Payable_Summary_of_Ac

Accounts Payable - Summary of Accounts Payable (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Accounts Payable [Abstract]	'	'
External services	$863,030	$678,813
Supplies	263,866	216,900
Other	25,007	103,652
Total accounts payable	$1,151,903	$999,365

Accrued_Expenses_and_Other_Cur2

Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Payables And Accruals [Abstract]	'	'
External services	$1,191,048	$900,580
Employee compensation	2,655,242	1,577,322
Other	221,626	229,539
Total accrued expenses and other current liabilities	$4,067,916	$2,707,441

Other_LongTerm_Liabilities_Sch

Other Long-Term Liabilities - Schedule of Other Long-Term Liabilities (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Other Long Term Liabilities [Abstract]	'	'
Accrued interest on loan payable	$497,134	'
Employee compensation	186,439	216,439
Net deferred tax liability	117,815	'
Total accrued expenses and other current liabilities	$801,388	$216,439

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)

12 Months Ended

0 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 20, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Incentive_Plan

Equity Incentive Plan [Member]

Equity Incentive Plan [Member]

Restricted Stock [Member]

Restricted Stock Three [Member]

Stock Appreciation Rights (SARs) [Member]

Stock Appreciation Rights (SARs) [Member]

Stock Appreciation Rights (SARs) [Member]

Options [Member]

Options [Member]

Options [Member]

Maximum [Member]

Maximum [Member]

Maximum [Member]

Minimum [Member]

Minimum [Member]

Restricted Stock [Member]

Options [Member]

Restricted Stock [Member]

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

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares authorized

225,000,000

225,000,000

'

'

8,553,608

'

'

'

'

'

'

'

'

225,000,000

'

'

75,000,000

'

Annual increase in number of shares of common stock

'

'

'

'

4.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

Aggregate limit of shares issuable to incentive stock option awards

'

'

'

'

3,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity incentive plans

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Initial grant of stock-based compensation in shares

'

'

'

6,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Increase in percentage of outstanding number of shares of common stock

'

'

'

4.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Term of years

'5 years 1 month 6 days

'6 years 4 months 24 days

'7 years 4 months 24 days

'

'

'

'

'

'

'

'4 years

'

'

'

'10 years

'10 years

'

'

Vesting period of grant date

'

'

'

'

'

'1 year

'

'3 years

'

'

'

'

'

'

'3 years

'3 years

'

'1 year

Restricted stock units vest and convert into shares of our common stock

'

'

'

'

'

'

'4 years

'

'

'

'

'

'

'

'

'

'

'

Percentage of vested grant yearly

'

'

'

'

'

'

'

'

'

'

25.00%

'

'

'

'

'

'

'

Percentage of vested grant monthly

'

'

'

'

'

'

'

'

'

'

75.00%

'

'

'

'

'

'

'

Unexercised vested option forfeiture

'

'

'

'

'

'

'

'

'

'

'3 months

'

'

'

'

'

'

'

Total unrecognized compensation expense

$4,275,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Vesting period

'3 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated fair value per share of options granted

$0

$0

$5.31

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Intrinsic value of options at time of exercise

2,214

4,319

11,293

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Estimated fair value

'

'

'

'

'

'

'

'

'

'

406,000

627,000

1,545,000

'

'

'

'

'

Exercise price

$20.42

'

'

'

'

'

'

$20

'

'

'

'

'

'

'

'

'

'

Reduced compensation expense

'

'

'

'

'

'

'

11,000

'

344,000

'

'

'

'

'

'

'

'

Total compensation expense

$2,608,670

$2,878,134

$3,260,937

'

'

'

'

'

$18,000

'

'

'

'

'

'

'

'

'

StockBased_Compensation_StockB

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Total stock-based compensation expense and effect on net loss	$2,608,670	$2,878,134	$3,260,937
Research and development expense [Member]	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Total stock-based compensation expense and effect on net loss	1,219,308	1,280,298	1,680,431
General and administrative expense [Member]	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'
Total stock-based compensation expense and effect on net loss	$1,389,362	$1,597,836	$1,580,506

StockBased_Compensation_Schedu

Stock-Based Compensation - Schedule of Fair Value Option Award, Assumptions (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'	'	'
Expected term (years)(1)	'5 years 1 month 6 days	'6 years 4 months 24 days	'7 years 4 months 24 days
Risk-free interest rate(2)	1.20%	1.40%	2.70%
Expected volatility(3)	89.30%	78.40%	79.70%
Expected dividend yield(4)	0.00%	0.00%	0.00%

StockBased_Compensation_Stock_

Stock-Based Compensation - Stock Option Activity (Detail) (USD $)	1 Months Ended	12 Months Ended
	Jan. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'	'	'	'	'
Number of Shares, Beginning balance	1,098,241	447,359	875,498	1,098,241	'
Number of Shares, Granted	6,000,000	'	'	3,750	'
Number of Shares, Exercised	'	-3,452	-3,629	-1,692	'
Number of Shares, Cancelled (forfeited and expired)	'	-15,649	-424,510	-224,801	'
Number of Shares, Ending balance	'	428,258	447,359	875,498	1,098,241
Weighted-Average Exercise Price, Beginning balance	$20.20	$19.59	$20.13	$20.20	'
Number of Shares, Exercisable	'	409,792	'	'	'
Weighted-Average Exercise Price, Granted	'	'	'	$7.30	'
Number of Shares, Vested and expected to vest	'	426,027	'	'	'
Weighted-Average Exercise Price, Exercised	'	$1	$1	$1.41	'
Weighted-Average Exercise Price, Cancelled (forfeited and expired)	'	$13.06	$20.86	$20.22	'
Weighted-Average Exercise Price, Ending balance	'	$19.97	$19.59	$20.13	$20.20
Aggregate Intrinsic Value, Beginning balance	$398,219	$2,175	'	$398,219	'
Weighted-Average Exercise Price, Exercisable	'	$20.42	'	'	'
Aggregate Intrinsic Value, Exercised	'	2,214	4,319	11,293	'
Weighted-Average Exercise Price, Vested and expected to vest	'	$20.02	'	'	'
Aggregate Intrinsic Value, Ending balance	'	'	2,175	'	398,219
Weighted-Average Remaining Contractual Term, Outstanding	'	'4 years 3 months 18 days	'5 years 1 month 6 days	'5 years 6 months	'6 years 1 month 6 days
Aggregate Intrinsic Value, Exercisable	'	'	'	'	'
Weighted-Average Remaining Contractual Term, Exercisable	'	'4 years 2 months 12 days	'	'	'
Aggregate Intrinsic Value, Vested and expected to vest	'	'	'	'	'
Weighted-Average Remaining Contractual Term, Vested and expected to vest	'	'4 years 3 months 18 days	'	'	'

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Changes in Unvested Options (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Weighted-Average Grant Date Fair Value, Granted	$0	$0	$5.31
Unvested stock options [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of Options, Beginning balance	64,503	'	'
Number of Options, Granted	'	'	'
Number of Options, Vested	-45,564	'	'
Number of Options, Cancelled	-473	'	'
Number of Options, Ending balance	18,466	'	'
Weighted-Average Grant Date Fair Value, Beginning balance	$8.67	'	'
Weighted-Average Grant Date Fair Value, Granted	'	'	'
Weighted-Average Grant Date Fair Value, Vested	$8.91	'	'
Weighted-Average Grant Date Fair Value, Cancelled	$7.82	'	'
Weighted-Average Grant Date Fair Value, Ending balance	$8.11	'	'

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, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number Outstanding	428,258
Weighted Average Remaining Term	'4 years 3 months 18 days
Weighted Average Exercise Price	$19.97
Aggregate Intrinsic Value	'
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	4,050
Weighted Average Remaining Term	'7 years 3 months 18 days
Weighted Average Exercise Price	$7.42
Aggregate Intrinsic Value	'
$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	250,949
Weighted Average Remaining Term	'5 years 3 months 18 days
Weighted Average Exercise Price	$12.65
Aggregate Intrinsic Value	'
$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	117,459
Weighted Average Remaining Term	'3 years 1 month 6 days
Weighted Average Exercise Price	$23.22
Aggregate Intrinsic Value	'
$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	19,800
Weighted Average Remaining Term	'1 year 10 months 24 days
Weighted Average Exercise Price	$36.46
Aggregate Intrinsic Value	'
$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	5,500
Weighted Average Remaining Term	'1 year 8 months 12 days
Weighted Average Exercise Price	$46.51
Aggregate Intrinsic Value	'
$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	30,500
Weighted Average Remaining Term	'1 year 8 months 12 days
Weighted Average Exercise Price	$53.94
Aggregate Intrinsic Value	'
Vested Options [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number Outstanding	409,792
Weighted Average Exercise Price	$20.42
Vested Options [Member] | Less than $10.00 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number Outstanding	2,677
Weighted Average Exercise Price	$7.45
Vested Options [Member] | $10.00 - $19.99 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number Outstanding	233,856
Weighted Average Exercise Price	$12.81
Vested Options [Member] | $20.00 - $29.99 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number Outstanding	117,459
Weighted Average Exercise Price	$23.22
Vested Options [Member] | $30.00 - $39.99 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number Outstanding	19,800
Weighted Average Exercise Price	$36.46
Vested Options [Member] | $40.00 - $49.99 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number Outstanding	5,500
Weighted Average Exercise Price	$46.51
Vested Options [Member] | $50.00 - $59.99 [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Number Outstanding	30,500
Weighted Average Exercise Price	$53.94

StockBased_Compensation_Summar1

Stock-Based Compensation - Summary of Restricted Stock Unit Activity (Detail) (Restricted stock units [Member], USD $)	12 Months Ended
	Dec. 31, 2013
Restricted stock units [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of RSUs, Beginning balance	1,534,200
Number of RSUs, Granted	2,421,965
Number of RSUs, Vested	-565,883
Number of RSUs, Cancelled	-64,000
Number of RSUs, Ending balance	3,326,282
Weighted Average Grant Date Fair Value, Beginning balance	$2.10
Weighted Average Grant Date Fair Value, Granted	$1.80
Weighted Average Grant Date Fair Value, Vested	$3.37
Weighted Average Grant Date Fair Value, Cancelled	$1.61
Weighted Average Grant Date Fair Value, Ending balance	$1.68

StockBased_Compensation_Summar2

Stock-Based Compensation - Summary of Restricted Stock Unit Activity (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Number of restricted unit vest and convert into common stock over next fiscal year	11,765
Number of restricted unit would vest over vesting period	55,000
Restricted stock units vested description after specified period	25
Restricted stock unit vest description	'55,000 of these restricted stock units vest and convert into shares of our common stock after one year from the date of grant. 2,355,200 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]	'
Vesting period of grant date	'1 year
Number of restricted unit would vest over vesting period	2,355,200
Restricted Stock Two [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Restricted stock units vest and convert into shares of our common stock	'4 years

StockBased_Compensation_Summar3

Stock-Based Compensation - Summary of Changes in Outstanding SARs (Detail) (Stock Appreciation Rights (SARs) [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Appreciation Rights (SARs) [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of SARs, Beginning balance	110,593	115,187	135,409
Number of SARs, Granted	'	'	'
Number of SARs, Exercised	'	'	'
Number of SARs, Forfeited	'	-4,594	-20,222
Number of SARs, Ending balance	110,593	110,593	115,187
SARs Exercisable, Ending balance	110,593	110,593	115,187
Weighted-average exercise price per share, Beginning balance	$20	$20	$20
Weighted-average exercise price per share, Ending balance	$20	$20	$20
Weighted-Average Exercise Price, Ending balance	$20	$20	$20

WindDown_and_Exit_Costs_Additi

Wind-Down and Exit Costs - Additional Information (Detail) (USD $)	12 Months Ended
	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	'

WindDown_and_Exit_Costs_Compon

Wind-Down and Exit Costs - Components of Wind-Down Reserve (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2013
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Accrued wind-down reserve at beginning of period	'	'	'	$854,000
Less actual expenses recorded against estimated reserve during the period	916,000	'	'	'
Revised reserve at period-end	'	'	'	854,000
Add deferred rent at period end	-435,967	-85,572	-1,302,543	'
Facility Closing In Rhode Island [Member]	'	'	'	'
Restructuring Cost and Reserve [Line Items]	'	'	'	'
Accrued wind-down reserve at beginning of period	854,000	1,683,000	'	'
Less actual expenses recorded against estimated reserve during the period	-916,000	-1,185,000	'	'
Additional expense recorded to revise estimated reserve	62,000	356,000	'	'
Revised reserve at period-end	'	854,000	'	'
Add deferred rent at period end	'	249,000	'	'
Total accrued wind-down expenses at period-end (current)	'	$1,103,000	'	'

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail)

1 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

1 Months Ended

1 Months Ended

Jul. 31, 2006

Dec. 31, 2013

Dec. 31, 2012

Oct. 31, 2013

Sep. 30, 2010

Dec. 31, 2013

Dec. 31, 2010

Dec. 31, 2013

Dec. 31, 2012

Mar. 31, 2013

Dec. 31, 2013

Oct. 31, 2013

Claim

USD ($)

USD ($)

NeuroSpheres [Member]

Caliper Life Sciences, Inc [Member]

Caliper Life Sciences, Inc [Member]

BMR-Gateway Boulevard LLC [Member]

BMR-Gateway Boulevard LLC [Member]

BMR-Gateway Boulevard LLC [Member]

Prologis, L.P [Member]

Prologis, L.P [Member]

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

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

GBP (£)

Commitment And Contingencies [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from the issuance of industrial revenue bonds

'

$5,000,000

'

'

'

'

'

'

'

'

'

'

Interest rate for remaining bond series

'

9.50%

'

'

'

'

'

'

'

'

'

'

Outstanding principal

'

125,000

331,000

'

'

'

'

'

'

'

'

'

Period of maturity

'

'2014-08

'

'

'

'

'

'

'

'

'

'

Term of lease

'

'15 years

'

'

'2 years

'

'11 years 6 months

'

'

'10 years

'

'3 years

Rent over term of lease

'

1,165,000

'

'

1,081,000

'

17,869,000

'

'

3,497,000

'

'

Lease term expires

'

30-Jun-13

'

'

'

30-Sep-13

'

'

'

'

'

'

Deferred rent under sublease agreement

'

34,366

'

'

'

'

'

1,434,000

1,389,000

'

391,000

'

Rental payments under the existing lease

'

'

'

'

'

'

'

'

'

'

'

£ 53,000

Number of patients violate claims of Neuralstem's activities

4

'

'

'

'

'

'

'

'

'

'

'

Shares issued

'

'

'

139,548

'

'

'

'

'

'

'

139,548

Commitments_and_Contingencies_2

Commitments and Contingencies - Summary of Components of Rent Expense (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Leases [Abstract]	'	'	'
Rent expense	$2,612,899	$2,932,104	$4,193,433
Sublease income	-53,726	-411,885	-424,847
Rent expense, net	$2,559,173	$2,520,219	$3,768,586

Commitments_and_Contingencies_3

Commitments and Contingencies - Future Minimum Payments Under All Leases and Bond Payable (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Loss Contingencies [Line Items]	'	'
Less current maturities, bond payable and loan payable	$125,000	$206,250
Bond payable and loan payable, less current maturities	'	125,000
Less current maturities, Capital Leases	21,316	6,888
Loan Payable [Member]	'	'
Loss Contingencies [Line Items]	'	'
2014	4,322,035	'
2015	4,322,035	'
2016	1,440,678	'
2017	'	'
2018	'	'
Thereafter	'	'
Total minimum lease payments	10,084,748	'
Less amounts representing interest	704,963	'
Principal amounts of bond payable and loan payable	9,379,785	'
Less current maturities, bond payable and loan payable	3,857,971	'
Bond payable and loan payable, less current maturities	5,521,814	'
Operating Leases [Member]	'	'
Loss Contingencies [Line Items]	'	'
Operating Leases, 2014	1,917,423	'
Operating Leases, 2015	1,912,217	'
Operating Leases, 2016	1,968,459	'
Operating Leases, 2017	2,014,706	'
Operating Leases, 2018	2,061,260	'
Operating Leases, Thereafter	8,196,910	'
Total minimum lease payments, Operating Leases	18,070,975	'
Capital Leases [Member]	'	'
Loss Contingencies [Line Items]	'	'
Capital Leases, 2014	24,284	'
Capital Leases, 2015	21,591	'
Capital Leases, 2016	9,454	'
Capital Leases, 2017	'	'
Capital Leases, 2018	'	'
Capital Leases, Thereafter	'	'
Total minimum lease payments, Capital Leases	55,329	'
Less amounts representing interest, Capital Leases	4,591	'
Principal amounts of bond payable, loan payable and capital lease obligations, Capital Leases	50,738	'
Less current maturities, Capital Leases	20,936	'
Capital Leases, Less current maturities	29,802	'
Bonds Payable [Member]	'	'
Loss Contingencies [Line Items]	'	'
2014	136,852	'
2015	'	'
2016	'	'
2017	'	'
2018	'	'
Thereafter	'	'
Total minimum lease payments	136,852	'
Less amounts representing interest	11,852	'
Principal amounts of bond payable and loan payable	125,000	'
Less current maturities, bond payable and loan payable	125,000	'
Bond payable and loan payable, less current maturities	'	'

Commitments_and_Contingencies_4

Commitments and Contingencies - Future Minimum Payments Under All Leases and Bond Payable (Parenthetical) (Detail) (USD $)	1 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Apr. 30, 2013	Sep. 30, 2012	Dec. 31, 2013
Loss Contingencies [Line Items]	'	'	'
Loan term	'	'	'3 years
CIRM Loan Agreement [Member]	'	'	'
Loss Contingencies [Line Items]	'	'	'
Proceeds from initial disbursement of the loan	'	'	$3.80
Approval of fund by California Institute for Regenerative Medicine (CIRM)	$19.30	'	'
Approval of fund by California Institute for Regenerative Medicine (CIRM) maximum period	'	'4 years	'4 years
Loan term	'	'10 years	'10 years

Warrant_Liability_Additional_I

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

1 Months Ended

12 Months Ended

1 Months Ended

6 Months Ended

12 Months Ended

1 Months Ended

1 Months Ended

1 Months Ended

12 Months Ended

Oct. 31, 2013

Oct. 31, 2013

Nov. 30, 2008

Dec. 31, 2013

Dec. 31, 2012

Oct. 31, 2013

Jun. 30, 2012

Dec. 31, 2012

Nov. 30, 2008

Dec. 31, 2013

Nov. 30, 2008

Nov. 30, 2009

Dec. 31, 2013

Nov. 30, 2009

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2011

Dec. 31, 2011

Outstanding warrants [Member]

Outstanding warrants [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

November 2008 Financing [Member]

November 2008 Financing [Member]

November 2008 Financing [Member]

November 2009 Financing [Member]

November 2009 Financing [Member]

November 2009 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

Common Stock [Member]

Common Stock [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series B Warrant [Member]

Series B Warrant [Member]

Series B Warrant [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Capital Units [Member]

Capital Units [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series B Warrant [Member]

Class of Warrant or Right [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of units sold to investors

'

'

'

'

'

'

'

'

1,379,310

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Price per unit

'

'

'

'

'

'

'

'

$14.50

'

'

$12.50

'

'

$1.25

'

'

'

'

'

'

'

'

'

'

'

Gross proceeds from units sold to investors

'

'

'

'

'

'

'

'

$20,000,000

'

'

$12,500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of securities callable by each warrant or right warrants

'

'

'

'

'

0.5

'

'

'

'

0.75

'

'

0.4

'

'

'

'

'

'

'

1

'

'

1

1

Exercise price of warrants

1.8

'

'

1.4

'

'

'

'

'

23

23

'

15

15

'

'

'

'

'

'

'

'

'

1.4

'

'

Proceeds from sale of stock

'

'

'

$538,000

$3,078,000

'

'

'

$18,637,000

'

'

$11,985,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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

'

1

1

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of securities callable by warrants

'

'

'

'

'

'

'

'

'

'

1,034,483

'

'

400,000

'

'

'

8,000,000

'

'

8,000,000

'

'

'

'

'

Number of units sold to investors

'

'

'

'

'

'

'

'

'

'

'

1,000,000

'

'

10,000,000

'

'

'

'

'

'

'

'

'

'

'

Number of warrants in each unit sold to institutional investors

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

Term of warrant

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'90 days

'

'

'

'

'

Warrant expiration

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'December 2016

'2012-May-02

'

'

'

'

'

'

'

'

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

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

'

Number of warrants exercised

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

384,534

2,198,571

'

'

2,700,000

'

'

'

'

'

'

Number of shares issued upon warrants exercise

12,845,500

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

384,534

2,700,000

'

'

'

Number of shares issued upon warrants exercise

'

'

'

'

'

'

2,700,000

2,198,571

'

'

'

'

'

'

'

'

2,700,000

'

'

'

'

384,534

2,198,571

'

'

'

Number of warrants expired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,300,000

'

'

'

'

'

'

'

Warrant_Liability_Assumptions_

Warrant Liability - Assumptions Used for Black-Scholes Option Pricing Model (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Class of Warrant or Right [Line Items]	'	'	'
Fair value of warrant liability	$5,541,809	$9,265,365	'
Change in fair value of warrant liability	-3,253,253	5,944,571	-6,612,092
Warrant Agreement 2008 [Member]	'	'	'
Class of Warrant or Right [Line Items]	'	'	'
Expected life (years)	'4 months 24 days	'1 year 4 months 24 days	'
Risk-free interest rate	0.10%	0.20%	'
Expected volatility	46.10%	108.20%	'
Expected dividend yield	0.00%	0.00%	'
Fair value of warrant liability	'	44,628	'
Change in fair value of warrant liability	($44,628)	'	'

Warrant_Liability_Assumptions_1

Warrant Liability - Assumptions Used for Black-Scholes Option Pricing Model1 (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Class of Warrant or Right [Line Items]	'	'	'
Fair value of warrant liability	$5,541,809	$9,265,365	'
Change in fair value of warrant liability	-3,253,253	5,944,571	-6,612,092
Warrant Agreement 2009 [Member]	'	'	'
Class of Warrant or Right [Line Items]	'	'	'
Expected life (years)	'1 year 3 months 18 days	'2 years 3 months 18 days	'
Risk-free interest rate	0.20%	0.30%	'
Expected volatility	48.20%	94.50%	'
Expected dividend yield	0.00%	0.00%	'
Fair value of warrant liability	'	63,340	'
Change in fair value of warrant liability	($63,340)	'	'

Warrant_Liability_Assumptions_2

Warrant Liability - Assumptions Used for Monte Carlo Simulation Model (Detail) (Series A Warrants [Member])	12 Months Ended
	Dec. 31, 2013
Series A Warrants [Member]	'
Class of Warrant or Right [Line Items]	'
Risk-free interest rate per year	0.80%
Expected volatility per year	85.20%
Expected dividend yield	0.00%
Expected life (years)	'3 years

Warrant_Liability_Summary_of_C

Warrant Liability - Summary of Changes in Fair Value of Warrant Liability (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Class of Warrant or Right [Line Items]	'
Number of Warrants, ending balance	9,551,378
Series A Warrants [Member]	'
Class of Warrant or Right [Line Items]	'
Number of Warrants, beginning balance	8,501,429
Number of Warrants, Less exercised	-384,534
Number of Warrants, ending balance	8,116,895
Fair value of warrant liability, beginning balance	$9,157,397
Fair value of warrants exercised	-470,303
Fair value, changes in fair value at period end	-3,145,285
Fair value of warrant liability, ending balance	$5,541,809

Warrant_Liability_Summary_of_W

Warrant Liability - Summary of Warrant Liability (Detail) (USD $)	Dec. 31, 2013	Oct. 31, 2013
Class of Warrant or Right [Line Items]	'	'
Number Outstanding	9,551,378	'
Exercise Price per share	'	1.8
Series A Warrants [Member]	'	'
Class of Warrant or Right [Line Items]	'	'
Number Outstanding	8,116,895	'
Exercise Price per share	1.4	'
November 2008 Financing [Member]	'	'
Class of Warrant or Right [Line Items]	'	'
Number Outstanding	1,034,483	'
Exercise Price per share	23	'
November 2009 Financing [Member]	'	'
Class of Warrant or Right [Line Items]	'	'
Number Outstanding	400,000	'
Exercise Price per share	15	'
Outstanding warrants [Member]	'	'
Class of Warrant or Right [Line Items]	'	'
Fair Value	5,541,809	'
Outstanding warrants [Member] | Series A Warrants [Member]	'	'
Class of Warrant or Right [Line Items]	'	'
Fair Value	5,541,809	'
Outstanding warrants [Member] | November 2008 Financing [Member]	'	'
Class of Warrant or Right [Line Items]	'	'
Fair Value	'	'
Outstanding warrants [Member] | November 2009 Financing [Member]	'	'
Class of Warrant or Right [Line Items]	'	'
Fair Value	'	'

Loan_Payable_Additional_Inform

Loan Payable - Additional Information (Detail) (USD $)	12 Months Ended		1 Months Ended			12 Months Ended	1 Months Ended	12 Months Ended		1 Months Ended	12 Months Ended
	Dec. 31, 2013	Oct. 31, 2013	Jul. 31, 2013	Apr. 30, 2013	Sep. 30, 2012	Dec. 31, 2013	Jan. 31, 2014	Dec. 31, 2013	Dec. 31, 2013	Apr. 30, 2013	Dec. 31, 2013
			CIRM Loan Agreement [Member]	CIRM Loan Agreement [Member]	CIRM Loan Agreement [Member]	CIRM Loan Agreement [Member]	Subsequent Events [Member]	Silicon Valley Bank Loan Agreement Warrant [Member]	Silicon Valley Bank Loan Agreement Warrant [Member]	Silicon Valley Bank [Member]	Silicon Valley Bank [Member]
							CIRM Loan Agreement [Member]		Common Stock [Member]
Debt Instrument [Line Items]	'	'	'	'	'	'	'	'	'	'	'
Proceeds from loan	$13,820,264	'	'	'	'	$3,820,264	'	'	'	$9,900,000	$10,000,000
Loan term	'3 years	'	'	'	'10 years	'10 years	'	'	'	'	'
Annual interest rate on loan	6.00%	'	'	'	'	'	'	'	'	'	'
Period of loan subject to interest payments only	'6 months	'	'	'	'	'	'	'	'	'	'
Period of loan subject to principal and interest payments	'30 months	'	'	'	'	'	'	'	'	'	'
Final fee payment at the end of loan term	1,000,000	'	'	'	'	'	'	'	'	'	'
Term of warrants expiration	'	'	'	'	'	'	'	'10 years	'	'	'
Number of shares of common stock acquired using warrants	'	'	'	'	'	'	'	'	293,531	'	'
Exercise price of warrants	'	1.8	'	'	'	'	'	1.7034	'	'	'
Warrants expiration period	'	'	'	'	'	'	'	'April 2023	'	'	'
Proceeds received under loan agreement	9,900,000	'	'	'	'	'	'	'	'	'	'
Initial carrying amount assigned to loan, net of discount	9,512,000	'	'	'	'	'	'	'	'	'	'
Fair value allocated to warrant	388,000	'	'	'	'	'	'	'	'	'	'
Cash discount	100,000	'	'	'	'	'	'	'	'	'	100,000
Note issuance costs	117,000	'	'	'	'	'	'	'	'	'	'
Deferred financing costs, discount and accretion percentage	9.00%	'	'	'	'	'	'	'	'	'	'
Approval of fund by California Institute for Regenerative Medicine (CIRM)	'	'	'	19,300,000	'	'	'	'	'	'	'
Approval of fund by California Institute for Regenerative Medicine (CIRM) maximum period	'	'	'	'	'4 years	'4 years	'	'	'	'	'
Loan interest rate description	'	'	'	'	'	'One year LIBOR rate plus two percent	'	'	'	'	'
LIBOR rate plus percentage	'	'	'	'	'	2.00%	'	'	'	'	'
LIBOR rate plus percentage increase	'	'	'	'	'	1.00%	'	'	'	'	'
Proceeds from initial disbursement of the loan	'	'	$3,800,000	'	'	$3,800,000	$3,800,000	'	'	'	'

Loan_Payable_Assumptions_Used_

Loan Payable - Assumptions Used for Black-Scholes Option Pricing Model (Detail) (Silicon Valley Bank Loan Agreement Warrant [Member])	12 Months Ended
	Dec. 31, 2013
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 $)	1 Months Ended	12 Months Ended
	Apr. 30, 2013	Dec. 31, 2013
Debt Instrument [Line Items]	'	'
Loan proceeds	'	$13,820,264
Cash discount	'	-100,000
Fair value of warrants issued	'	-387,576
Initial carrying value	'	13,332,688
Repayment of principal	'	-620,215
Accretion of discount	'	196,771
Carrying value of total loan payable at 12/31/2013 (current and non-current)	'	12,909,244
Carrying value of loan payable, current portion	'	3,664,370
Carrying value of loan payable, non-current portion	'	9,244,874
Carrying value of total loan payable at 12/31/2013 (current and non-current)	'	12,909,244
Silicon Valley Bank [Member]	'	'
Debt Instrument [Line Items]	'	'
Loan proceeds	9,900,000	10,000,000
Cash discount	'	-100,000
Fair value of warrants issued	'	-387,576
Initial carrying value	'	9,512,424
Repayment of principal	'	-620,215
Accretion of discount	'	196,771
Carrying value of total loan payable at 12/31/2013 (current and non-current)	'	9,088,980
Carrying value of loan payable, current portion	'	3,664,370
Carrying value of loan payable, non-current portion	'	5,424,610
Carrying value of total loan payable at 12/31/2013 (current and non-current)	'	9,088,980
CIRM Loan Agreement [Member]	'	'
Debt Instrument [Line Items]	'	'
Loan proceeds	'	3,820,264
Cash discount	'	'
Fair value of warrants issued	'	'
Initial carrying value	'	3,820,264
Repayment of principal	'	'
Accretion of discount	'	'
Carrying value of total loan payable at 12/31/2013 (current and non-current)	'	3,820,264
Carrying value of loan payable, current portion	'	'
Carrying value of loan payable, non-current portion	'	3,820,264
Carrying value of total loan payable at 12/31/2013 (current and non-current)	'	$3,820,264

Common_Stock_Additional_Inform

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

1 Months Ended

9 Months Ended

12 Months Ended

6 Months Ended

1 Months Ended

12 Months Ended

6 Months Ended

12 Months Ended

6 Months Ended

12 Months Ended

12 Months Ended

1 Months Ended

6 Months Ended

12 Months Ended

6 Months Ended

12 Months Ended

Oct. 31, 2013

Dec. 31, 2011

Jan. 31, 2011

Sep. 30, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Jun. 30, 2013

Oct. 31, 2013

Oct. 31, 2013

Nov. 30, 2008

Dec. 31, 2013

Dec. 31, 2012

Jun. 30, 2012

Dec. 31, 2012

Dec. 31, 2011

Jun. 30, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Oct. 31, 2013

Jun. 30, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2011

Dec. 31, 2010

Jun. 30, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Institutional Investors [Member]

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

Outstanding warrants [Member]

Outstanding warrants [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series B Warrant [Member]

Series B Warrant [Member]

Series B Warrant [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Series A Warrants [Member]

Minimum [Member]

Maximum [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Common Stock [Member]

Patents

Series A Warrants [Member]

Series A Warrants [Member]

Institutional Investors [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

December 2011 Financing [Member]

Series A Warrants [Member]

Subsidiary, Sale of Stock [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares authorized

'

'

'

'

225,000,000

225,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

75,000,000

225,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Common stock issued in public offering

12,845,500

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

8,000,000

'

'

'

'

'

'

'

'

'

'

329,131

384,534

2,700,000

'

Sale of common stock and warrant, price per share

$1.45

'

$10

'

$1.91

$2.12

$2.47

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from issuance of common stock and warrants

$17,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common stock, par value

$0.01

'

'

'

$0.01

$0.01

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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

'

'

'

'

'

'

'

'

'

1

1

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

Number of securities callable by each warrant or right warrants

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.5

'

'

'

'

'

'

1

'

'

Warrant exercise price

1.8

'

'

'

'

'

'

'

'

'

'

1.4

'

'

'

1.25

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.4

Warrant expiration period

'5 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares available to sale

'

'

'

'

'

'

'

30,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common stock, sold

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,645,639

'

'

'

Sale of stock, price per share

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$1.82

'

'

'

Gross proceeds from common stock

'

'

9,400,000

'

23,491,597

19,747,550

19,774,820

3,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Exercise period of rights

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Additional amounts of common stock to sell

'

'

'

'

'

'

'

27,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrants termination agreement

'

'

'

'

'2013-10

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common stock, sold

'

'

1,000,000

'

1,733,771

9,647,471

525,116

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Sales agent is paid compensation equal to 3% of gross proceeds

'

'

'

'

3.00%

3.00%

3.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of warrants exercised

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

384,534

'

'

'

'

384,534

'

'

'

'

'

'

'

'

'

'

'

Proceeds from sale of stock

'

'

'

'

'

'

'

'

'

'

'

538,000

3,078,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of warrants exercised

'

'

'

'

'

'

'

'

'

'

'

'

'

2,700,000

'

'

'

'

2,198,571

'

'

'

384,534

2,198,571

'

'

'

'

'

'

'

'

'

'

Gross proceeds

'

'

'

'

530,097

6,256,438

'

'

'

'

'

'

'

3,375,000

'

10,000,000

'

'

3,078,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of warrants expired

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrant expiration date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2-May-12

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares issued upon warrants exercise

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,700,000

'

2,700,000

2,198,571

'

'

'

'

384,534

2,198,571

'

Number of warrants issued

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Series B Warrants issued in public offering

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

8,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Exercise price of warrant

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$1.40

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Class of warrant date until which warrants exercisable description

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'Will expire on the fifth anniversary of the closing date of the initial financing transaction in December 2011.

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warrant right and unit combination description

'

'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.

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock options granted to investors

'

'

6,000,000

'

'

'

3,750

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Grant date value

'

'

$10

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock options given to investor expiry date

'

'

18-Feb-11

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of patents acquired

'

'

'

'

'

'

'

'

6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Shares issued

'

'

'

'

'

'

'

'

139,548

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

37,506,305

55,138,311

22,427,955

12,731,287

'

'

'

'

Fair value of common Stock

'

'

'

$200,000

'

'

'

'

$200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

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, 2013
Class of Stock [Line Items]	'
Share reserved for share-based compensation	28,575,807
Outstanding warrants [Member]	'
Class of Stock [Line Items]	'
Share reserved for share-based compensation	16,267,659
Stock Compensation Plan [Member]	'
Class of Stock [Line Items]	'
Share reserved for share-based compensation	12,308,148

Deferred_Revenue_Additional_In

Deferred Revenue - Additional Information (Detail) (Nonsoftware License Arrangement [Member], Stem Cell Therapeutics [Member], USD $)	12 Months Ended
	Dec. 31, 2013
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	$107,000
Deferred revenue, Prepaid orders for products	$23,000

401k_Plan_Additional_Informati

401(k) Plan - Additional Information (Detail) (401 (k) Plan [Member], USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
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	$132,000	$130,000	$165,000

Income_Taxes_Loss_Before_Incom

Income Taxes - Loss Before Income Tax Attributable to Geographic Location (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]	'	'
United States	$26,080,000	$28,356,000
Foreign	359,000	133,000
Total loss before income taxes	$26,439,000	$28,489,000

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Unrecognized tax benefits	$0	$0
Increase in valuation allowances	10,270,000	864,000
Tax liabilities	0	'
Tax related interest	0	'
Tax related penalties	0	'
Domestic Tax Authority [Member]	'	'
Net operating loss carry forward	154,541,000	'
Operating loss carryforward expiration period description	'2018 through 2033	'
Excess deductions from exercise of stock option	1,792,000	'
State and Local Jurisdiction [Member]	'	'
Net operating loss carry forward	43,747,000	'
Operating loss carryforward expiration period description	'2014 through 2033	'
Operating loss carry forward for the exercise of stock	1,362,000	'
Foreign Tax Authority [Member]	'	'
Net operating loss carry forward	11,896,000	'
Capital Loss Carryforward [Member] | Domestic And State [Member]	'	'
Operating loss carryforward expiration period description	'2014 through 2016	'
Capital loss carry forward for federal and state income tax purposes	1,592,000	'
Research and Development [Member] | Domestic Tax Authority [Member]	'	'
Operating loss carryforward expiration period description	'2018 through 2033	'
Capital loss carry forward for federal and state income tax purposes	5,656,000	'
Research and Development [Member] | State and Local Jurisdiction [Member]	'	'
Capital loss carry forward for federal and state income tax purposes	4,962,000	'
State research and development tax credits net of federal tax effect	$3,275,000	'

Income_Taxes_Components_of_Def

Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:	'	'
Capitalized research and development costs	$59,426,000	$53,824,000
Net operating losses	56,906,000	53,687,000
Research and development credits	8,931,000	7,777,000
Accrued wind down cost	'	292,000
Stock-based compensation	1,063,000	853,000
Capital loss carryover	541,000	544,000
Fixed assets	452,000	430,000
Other	1,289,000	1,002,000
Gross deferred tax assets	128,608,000	118,409,000
Valuation allowance	-128,315,000	-118,045,000
Total deferred tax assets	293,000	364,000
Deferred tax liability:	'	'
Intangible assets	-293,000	-364,000
Total deferred tax liability	-293,000	-364,000
Net deferred tax assets	$0	'

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of Federal Income Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Abstract]	'	'	'
Statutory federal income tax (benefit) rate	-34.00%	-34.00%	-34.00%
State income tax (benefit) rate	'	-3.30%	-3.40%
Increase resulting from:	'	'	'
Expenses not deductible for taxes	0.50%	8.80%	-6.70%
Increase in valuation allowance	38.80%	3.70%	32.80%
Change in state deferred tax rate	1.10%	17.70%	0.00%
Change in foreign deferred tax rate	0.90%	1.80%	0.00%
Expiration of tax attributes	0.50%	5.30%	11.30%
Prior year true up	-0.70%	'	'
Tax credits	-3.00%	'	'
Warrant valuation	-4.10%	'	'
Effective tax (benefit) rate	0.00%	0.00%	0.00%

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income - Summary of Changes in Accumulated Other Comprehensive Loss by Component (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income [Line Items]	'	'	'
Beginning balance	$193,177	'	'
Other comprehensive income before reclassifications	58,924	'	'
Amounts reclassified from accumulated other comprehensive loss	'	'	'
Other comprehensive income (loss)	58,924	152,464	-79,009
Ending balance	252,101	193,177	'
Unrealized Gain (Loss) on Other Available-for-Sale Securities [Member]	'	'	'
Accumulated Other Comprehensive Income [Line Items]	'	'	'
Beginning balance	-1,356	'	'
Other comprehensive income before reclassifications	1,356	'	'
Amounts reclassified from accumulated other comprehensive loss	'	'	'
Other comprehensive income (loss)	1,356	'	'
Ending balance	'	'	'
Foreign Currency Translation [Member]	'	'	'
Accumulated Other Comprehensive Income [Line Items]	'	'	'
Beginning balance	194,533	'	'
Other comprehensive income before reclassifications	57,568	'	'
Amounts reclassified from accumulated other comprehensive loss	'	'	'
Other comprehensive income (loss)	57,568	'	'
Ending balance	$252,101	'	'

Quarterly_Financial_Data_Summa

Quarterly Financial Data - Summary of Quarterly Financial Data (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Total revenue	$313,000	$325,000	$282,000	$284,000	$211,000	$264,000	$249,000	$644,000	$1,203,270	$1,367,955	$1,220,670
Cost of Sales	86,000	86,000	78,000	67,000	55,000	72,000	64,000	72,000	316,628	263,188	214,811
Operating expenses	9,697,000	6,895,000	6,425,000	6,475,000	6,949,000	5,269,000	5,534,000	5,898,000	29,492,087	23,650,443	29,082,222
Other income (expense), net	2,508,000	-536,000	353,000	-159,000	4,034,000	-11,260,000	6,183,000	-4,903,000	68,497	33,693	109,404
Net income (loss)	($6,962,000)	($7,192,000)	($5,869,000)	($6,416,000)	($2,758,000)	($16,337,000)	$833,000	($10,229,000)	($26,439,159)	($28,491,153)	($21,328,538)
Basic and diluted net income (loss) per share	($0.13)	($0.17)	($0.15)	($0.17)	($0.07)	($0.54)	$0.03	($0.45)	($0.61)	($0.99)	($1.50)