Stockholders’ Equity (Details) - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended
	Nov. 01, 2017	Sep. 30, 2017	Sep. 30, 2016	Oct. 30, 2017	Dec. 31, 2016
Warrant exercises, Shares		409,000
Warrant exercises, Proceeds		$ 287
Stock option exercises, Shares		7,000
Stock option exercises, Proceeds		$ 17
Employee stock purchases, Shares		132,000	79,000
Employee stock purchases, Proceeds		$ 184	$ 111
Total, Shares		548,000	79,000
Total, Proceeds		$ 488	$ 111
Common Stock, Par or Stated Value Per Share		$ 0.001			$ 0.001
Underwriting
Shares sold in public offering (in shares)	38,333,334
Common Stock, Par or Stated Value Per Share				$ 0.001
Stock price (in dollars per share)				$ 1.50