Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash Flows From Operating Activities:
Net loss	$ (19,784)us-gaap_ProfitLoss	$ (12,318)us-gaap_ProfitLoss	$ (17,068)us-gaap_ProfitLoss
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	2,459us-gaap_ShareBasedCompensation	1,669us-gaap_ShareBasedCompensation	1,851us-gaap_ShareBasedCompensation
Stock issued for exclusive channel collaboration agreement	0	0	7,815
Stock issued for acquisition of program assets	0	0	1,169
Stock issued for license agreement	0syn_StockIssuedForLicenseAgreement	425syn_StockIssuedForLicenseAgreement	0syn_StockIssuedForLicenseAgreement
Change in fair value of warrant liabilities	(620)us-gaap_FairValueAdjustmentOfWarrants	0us-gaap_FairValueAdjustmentOfWarrants	0us-gaap_FairValueAdjustmentOfWarrants
Depreciation	20us-gaap_Depreciation	43us-gaap_Depreciation	63us-gaap_Depreciation
Provision for uncollectible accounts receivable	0	0	442
Provision for uncollectible note and interest receivables	0	763	0
Loss on sale of equipment	0us-gaap_GainLossOnDispositionOfAssets	58us-gaap_GainLossOnDispositionOfAssets	0us-gaap_GainLossOnDispositionOfAssets
Impairment loss on equipment	0syn_EquipmentImpairmentLoss	121syn_EquipmentImpairmentLoss	47syn_EquipmentImpairmentLoss
Gain on sale of discontinued operations	0	0	(677)
Changes in operating assets and liabilities:
Accounts receivable	0	0	14
Prepaid expenses and other current assets	43	855	(2,544)
Deposits and other assets	(2)	33	(6)
Accounts payable	854	(253)	7
Accrued expenses	416	885	(29)
Accrued employee benefits	535	0	0
Net Cash Used In Operating Activities	(16,079)	(7,719)	(8,916)
Cash Flows From Investing Activities:
Purchases of property and equipment	(48)	(36)	(10)
Net Cash Used In Investing Activities	(48)	(36)	(10)
Cash Flows From Financing Activities:
Proceeds from issuance of common stock for stock option exercises	4	232	2,082
Proceeds from issuance of common stock	20,668	13,224	10,800
Cash paid as direct offering costs	(1,645)syn_DirectOfferingCost	(1,031)syn_DirectOfferingCost	(680)syn_DirectOfferingCost
Cash received from issuance of stock to non-controlling interest	0	1	0
Net Cash Provided By Financing Activities	19,027	12,426	12,202
Net increase in cash	2,900us-gaap_CashPeriodIncreaseDecrease	4,671us-gaap_CashPeriodIncreaseDecrease	3,276us-gaap_CashPeriodIncreaseDecrease
Cash at beginning of period	14,625	9,954	6,678
Cash at end of period	17,525	14,625	9,954
Supplemental disclosures of cash flow information:
Cash paid for interest	0us-gaap_InterestPaid	0us-gaap_InterestPaid	0us-gaap_InterestPaid
Cash paid for taxes	$ 0us-gaap_IncomeTaxesPaid	$ 0us-gaap_IncomeTaxesPaid	$ 0us-gaap_IncomeTaxesPaid

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