Significant Accounting Policies - Changes in Fair Value of the Company's Warrants (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 01, 2017	Dec. 31, 2016
Fair Value, Liabilities Measured on Recurring Basis [Roll Forward]
Liability at beginning of the period	$ 107
Fair value of warrants exercised in the period	(129)
Increase (decrease) in fair value of warrants	22
Liability at end of the period	$ 0
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants exercised (in shares)	179,000	0
Warrants and rights outstanding	$ 0			$ 107
Proceeds from warrant exercises	$ 353	$ 0
Class of warrant expired (in shares)			22,000
Cashless exercise provision
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Warrants exercised (in shares)	0	0