Condensed consolidated statements of operations and comprehensive loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Operating expenses
Research and development	$ 10,508	$ 5,777
General and administrative	4,309	2,745
Total operating expenses	14,817	8,522
Other income, net (Note 6)	194	206
Net loss	$ (14,623)	$ (8,316)
Net loss per common stock - basic and diluted (Note 7)	$ (0.62)	$ (0.36)
Basic and diluted weighted average number of common stock outstanding	23,480,757	23,423,150
Comprehensive loss:
Net loss	$ (14,623)	$ (8,316)
Other comprehensive income (loss) - unrealized gain (loss) on available-for-salesecurities	46	(36)
Comprehensive loss	$ (14,577)	$ (8,352)

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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