Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Research and Development Expense [Member]
Included in operating expenses, above, are the following amounts for non-cash stock based compensation expense:
Allocated share-based compensation	$ 308	$ 110
General and Administrative Expense [Member]
Included in operating expenses, above, are the following amounts for non-cash stock based compensation expense:
Allocated share-based compensation	558	297
Research and development	4,349	2,633
General and administrative	2,470	1,987
Total operating expenses	6,819	4,620
Loss from operations	(6,819)	(4,620)
Investment income	56	$ 40
Other income, net	211
Total other income	267	$ 40
Net loss	(6,552)	(4,580)
Unrealized gain on available-for-sale investments	23	6
Comprehensive loss	(6,529)	(4,574)
Net loss attributable to common stockholders	$ (6,552)	$ (4,580)
Net loss per share attributable to common stockholders - basic and diluted (in dollars per share)	$ (0.40)	$ (0.28)
Weighted-average common shares outstanding used in net loss per share attributable to common stockholders - basic and diluted (in shares)	16,507,586	16,448,688
Allocated share-based compensation	$ 866	$ 407
Included in other income, net, above, are the following amounts from forward foreign currency contracts:
Realized gains from forward foreign currency contracts	6
Unrealized gains from forward foreign currency contracts	178
Total	$ 184