Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 46,024	$ 48,490
Marketable securities	51,666	42,986
Prepaid expenses and other current assets	1,656	765
Total current assets	99,346us-gaap_AssetsCurrent	92,241us-gaap_AssetsCurrent
Property and equipment, net	1,024us-gaap_PropertyPlantAndEquipmentNet	1,553us-gaap_PropertyPlantAndEquipmentNet
Other assets	305us-gaap_OtherAssetsNoncurrent	1,409us-gaap_OtherAssetsNoncurrent
Total assets	100,675us-gaap_Assets	95,203us-gaap_Assets
Current liabilities:
Accounts payable	3,139us-gaap_AccountsPayableCurrent	6,589us-gaap_AccountsPayableCurrent
Accrued contract research costs	12,317snta_AccruedContractResearchCosts	10,407snta_AccruedContractResearchCosts
Other accrued liabilities	6,177	5,718
Current portion of capital lease obligations	42us-gaap_CapitalLeaseObligationsCurrent	42us-gaap_CapitalLeaseObligationsCurrent
Current portion of term loans	9,214us-gaap_SecuredDebtCurrent	9,451us-gaap_SecuredDebtCurrent
Total current liabilities	30,889us-gaap_LiabilitiesCurrent	32,207us-gaap_LiabilitiesCurrent
Long-term liabilities:
Capital lease obligations, net of current portion	43	85
Term loans, net of current portion	4,607us-gaap_SecuredLongTermDebt	13,820us-gaap_SecuredLongTermDebt
Total long-term liabilities	4,650us-gaap_LiabilitiesNoncurrent	13,905us-gaap_LiabilitiesNoncurrent
Total liabilities	35,539us-gaap_Liabilities	46,112us-gaap_Liabilities
Commitments and contingencies (Note 11)
Stockholders' equity:
Preferred stock, par value $0.0001 per share Authorized: 5,000,000 shares at December 31, 2014 and 2013; no shares issued and outstanding at December 31, 2014 and 2013
Common stock, par value $0.0001 per share Authorized: 200,000,000 shares at December 31, 2014 and December 31, 2013; 109,120,670 and 85,232,506 shares issued and outstanding at December 31, 2014 and 2013, respectively	11us-gaap_CommonStockValue	9us-gaap_CommonStockValue
Additional paid-in-capital	702,694	600,477
Accumulated other comprehensive income	4	17
Accumulated deficit	(637,573)	(551,412)
Total stockholders' equity	65,136us-gaap_StockholdersEquity	49,091us-gaap_StockholdersEquity
Total liabilities and stockholders' equity	$ 100,675	$ 95,203

The carrying value as of the balance sheet date of obligations incurred and payable relating to service fees paid to contract manufacturers in connection with the production of clinical drug supplies and to contract research organizations in connection with preclinical studies and clinical trials. Used to reflect the current portion of liabilities (due within one year or within the normal operating cycle if longer).

No definition available.