Organization and Summary of Significant Accounting Policies - Summary of Restricted Stock Unit Activity (Details) - Restricted stock units shares in Thousands	9 Months Ended
	Sep. 30, 2018 $ / shares shares
Number of Shares
Unvested, beginning balance (in shares) | shares	718
Vested (in shares) | shares	(288)
Forfeited (in shares) | shares	(11)
Unvested, ending balance (in shares) | shares	419
Weighted Average Grant Date Fair Value
Unvested, beginning balance (in usd per share) | $ / shares	$ 1.57
Vested (in usd per share) | $ / shares	1.82
Forfeited (in usd per share) | $ / shares	1.32
Unvested, ending balance (in usd per share) | $ / shares	$ 1.40