Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 65,917	$ 72,026
Marketable securities	9,464	12,015
Accounts receivable	1,205	215
Prepaid expenses and other current assets	464	686
Total current assets	77,050	84,942
Property, plant and equipment, net	2,353	2,476
Total assets	79,403	87,418
Current liabilities:
Accounts payable and accrued expenses (note 7)	1,530	2,664
Deferred revenue	8,724	11,622
Fair value of liability classified stock options	6,298
Total current liabilities	16,552	14,286
Deferred revenue, less current portion		157
Deferred tenant inducements	180	196
Total liabilities	16,732	14,639
Shareholders’ equity:
Common shares, without par value; unlimited shares authorized; issued and outstanding: 14,222,275 (December 31, 2014 - 14,181,333)	147,508	147,157
Additional paid-in capital	29,083	30,346
Accumulated deficit	(112,930)	(103,734)
Accumulated other comprehensive loss	(990)	(990)
Shareholders' equity	62,671	72,779
Total liabilities and shareholders’ equity	$ 79,403	$ 87,418
Commitments and contingencies (note 10)

Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits.

Name:	us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.