Long-Term Obligations and Commitments, Operating Leases (Details) - Office and Laboratory Space [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) Option	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Annual Future Minimum Payments Under Operating Leases [Abstract]
2018	$ 864
2019	636
2020	477
2021	147
Total minimum payments	2,124
Rent expense	1,700	$ 2,000	$ 2,000
Deferred rent	$ 100	$ 2,100
Building [Member]
Operating Leases [Abstract]
Number of options to extend lease | Option	2
Term of lease extension	5 years