Organization and Basis of Presentation (Details) - USD ($) $ / shares in Units, $ in Thousands		1 Months Ended
	Mar. 23, 2018	May 10, 2018	Mar. 31, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents			$ 19,688	$ 14,680
Net working capital			15,100
Accumulated deficit			$ 156,294	$ 152,331
Subsidiary, Sale of Stock [Line Items]
Net proceeds from sale of stock	$ 9,000
Number of shares sold (in shares)	7,968,128
Price per share (in usd per share)	$ 1.13
Number of warrant sold (in shares)	7,968,128
Warrant price per unit (usd per unit)	$ 0.125
Share of stock for each warrant (in shares)	1
Exercise price of warrants (usd per share)	$ 1.20
Expiration period	5 years
Subsequent Event
Subsidiary, Sale of Stock [Line Items]
Number of warrant sold (in shares)		5,200,000
Proceeds from exercise of warrants		$ 4,200