Stockholders' Equity (Common Stock are Reserved for Future Issuance) (Details) - shares shares in Thousands	Jun. 30, 2018	Dec. 31, 2017
Equity [Abstract]
Warrants outstanding (in shares)	1,812	963
Series A Convertible Preferred (in shares)	1,345
Stock options outstanding (in shares)	473	10
Options reserved for future issuance under the Company's 2017 Incentive Plan (in shares)	343
Shares reserved for future issuance under the Employee Stock Purchase Plan (in shares)	115
Restricted stock units (in shares)	13
Total reserved for future issuance (in shares)	4,101