Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 9,906,373	$ 23,644,542
Other current assets	758,943us-gaap_OtherAssetsCurrent	1,122,576us-gaap_OtherAssetsCurrent
Total current assets	10,665,316us-gaap_AssetsCurrent	24,767,118us-gaap_AssetsCurrent
Property & equipment, net of accumulated depreciation of $2,099,389 and $1,718,477, respectively	1,098,104us-gaap_PropertyPlantAndEquipmentNet	1,295,024us-gaap_PropertyPlantAndEquipmentNet
Other long-term assets	38,939us-gaap_OtherAssetsNoncurrent	177,666us-gaap_OtherAssetsNoncurrent
Total assets	11,802,359us-gaap_Assets	26,239,808us-gaap_Assets
Current liabilities:
Accounts payable	702,494us-gaap_AccountsPayableCurrent	696,155us-gaap_AccountsPayableCurrent
Accrued expenses	1,199,184us-gaap_AccruedLiabilitiesCurrent	1,232,990us-gaap_AccruedLiabilitiesCurrent
Deferred revenue	1,230,746us-gaap_DeferredRevenueCurrent	1,395,348us-gaap_DeferredRevenueCurrent
Total current liabilities	3,132,424us-gaap_LiabilitiesCurrent	3,324,493us-gaap_LiabilitiesCurrent
Long term liabilities:
Deferred revenue	1,230,748us-gaap_DeferredRevenueNoncurrent	2,338,041us-gaap_DeferredRevenueNoncurrent
Total liabilities	4,363,172us-gaap_Liabilities	5,662,534us-gaap_Liabilities
Commitments and contingencies
Stockholders' equity:
Preferred stock, no par value, 10,000,000 shares authorized, none issued and outstanding	0us-gaap_PreferredStockValue	0us-gaap_PreferredStockValue
Common stock, $0.01 par value, 100,000,000 shares authorized, 28,234,751 and 27,546,058 shares issued and outstanding	282,348us-gaap_CommonStockValue	275,461us-gaap_CommonStockValue
Additional paid in capital	148,477,047us-gaap_AdditionalPaidInCapital	146,569,758us-gaap_AdditionalPaidInCapital
Accumulated deficit	(141,320,208)	(126,267,945)
Total stockholders' equity	7,439,187us-gaap_StockholdersEquity	20,577,274us-gaap_StockholdersEquity
Total liabilities and stockholders' equity	$ 11,802,359	$ 26,239,808

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19

-Subparagraph a

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(a))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682